Warnings in docs can make sphinx build fail

[morcuended]

Currently, Sphinx generates 14 warnings when building the docs. Sphinx treats these warnings as errors, and if the number keeps increasing, the docs' build can fail as happened in https://github.com/cta-observatory/cta-lstchain/actions/runs/11231362777/job/31224128576

While they are not problematic for the code, I think they indicate problems with the code.

I leave them here to fix them at some point.

WARNING: autodoc: failed to import function 'parse_cfg_bytestring' from module 'lstchain.io.io'; the following exception was raised:
Traceback (most recent call last):
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/util/inspect.py", line 374, in safe_getattr
    return getattr(obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'lstchain.io.io' has no attribute 'parse_cfg_bytestring'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/importer.py", line 209, in import_object
    obj = attrgetter(obj, mangled_name)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 329, in get_attr
    return autodoc_attrgetter(self.env.app, obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 2844, in autodoc_attrgetter
    return safe_getattr(obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/util/inspect.py", line 390, in safe_getattr
    raise AttributeError(name) from exc
AttributeError: parse_cfg_bytestring

WARNING: autodoc: failed to import function 'interpolate_al_cuts' from module 'lstchain.high_level.interpolate'; the following exception was raised:
Traceback (most recent call last):
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/util/inspect.py", line 374, in safe_getattr
    return getattr(obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'lstchain.high_level.interpolate' has no attribute 'interpolate_al_cuts'. Did you mean: 'interpolate_cuts'?

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/importer.py", line 209, in import_object
    obj = attrgetter(obj, mangled_name)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 329, in get_attr
    return autodoc_attrgetter(self.env.app, obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 2844, in autodoc_attrgetter
    return safe_getattr(obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/util/inspect.py", line 390, in safe_getattr
    raise AttributeError(name) from exc
AttributeError: interpolate_al_cuts

WARNING: autodoc: failed to import function 'interpolate_gh_cuts' from module 'lstchain.high_level.interpolate'; the following exception was raised:
Traceback (most recent call last):
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/util/inspect.py", line 374, in safe_getattr
    return getattr(obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'lstchain.high_level.interpolate' has no attribute 'interpolate_gh_cuts'. Did you mean: 'interpolate_cuts'?

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/importer.py", line 209, in import_object
    obj = attrgetter(obj, mangled_name)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 329, in get_attr
    return autodoc_attrgetter(self.env.app, obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 2844, in autodoc_attrgetter
    return safe_getattr(obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/util/inspect.py", line 390, in safe_getattr
    raise AttributeError(name) from exc
AttributeError: interpolate_gh_cuts

WARNING: autodoc: failed to import function 'tune_nsb_on_waveform' from module 'lstchain.image.modifier'; the following exception was raised:
Traceback (most recent call last):
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/util/inspect.py", line 374, in safe_getattr
    return getattr(obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'lstchain.image.modifier' has no attribute 'tune_nsb_on_waveform'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/importer.py", line 209, in import_object
    obj = attrgetter(obj, mangled_name)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 329, in get_attr
    return autodoc_attrgetter(self.env.app, obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 2844, in autodoc_attrgetter
    return safe_getattr(obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/util/inspect.py", line 390, in safe_getattr
    raise AttributeError(name) from exc
AttributeError: tune_nsb_on_waveform

/Users/dmorcuende/Software/CTA/LST/cta-lstchain/docs/api/lstchain.tools.lstchain_create_dl3_file.DataReductionFITSWriter.rst:11: WARNING: autosummary: failed to import DataReductionFITSWriter.final_irf_file.
Possible hints:
* ModuleNotFoundError: No module named 'lstchain.tools.lstchain_create_dl3_file.DataReductionFITSWriter'; 'lstchain.tools.lstchain_create_dl3_file' is not a package
* KeyError: 'DataReductionFITSWriter'
* AttributeError: type object 'DataReductionFITSWriter' has no attribute 'final_irf_file'
* PycodeError: no source found for module 'builtins'
* ModuleNotFoundError: No module named 'DataReductionFITSWriter'
* AttributeError: type object 'DataReductionFITSWriter' has no attribute 'DataReductionFITSWriter'
WARNING: autodoc: failed to import attribute 'DataReductionFITSWriter.final_irf_file' from module 'lstchain.tools.lstchain_create_dl3_file'; the following exception was raised:
Traceback (most recent call last):
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/importer.py", line 209, in import_object
    obj = attrgetter(obj, mangled_name)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 329, in get_attr
    return autodoc_attrgetter(self.env.app, obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx/ext/autodoc/__init__.py", line 2842, in autodoc_attrgetter
    return func(obj, name, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/dmorcuende/.local/miniconda/envs/lstchain-tmp/lib/python3.12/site-packages/sphinx_automodapi/autodoc_enhancements.py", line 61, in type_object_attrgetter
    return getattr(obj, attr, *defargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: type object 'DataReductionFITSWriter' has no attribute 'final_irf_file'

looking for now-outdated files... none found
pickling environment... done
checking consistency... /Users/dmorcuende/Software/CTA/LST/cta-lstchain/docs/api/lstchain.high_level.interpolate.interpolate_al_cuts.rst: WARNING: document isn't included in any toctree
/Users/dmorcuende/Software/CTA/LST/cta-lstchain/docs/api/lstchain.high_level.interpolate.interpolate_gh_cuts.rst: WARNING: document isn't included in any toctree
/Users/dmorcuende/Software/CTA/LST/cta-lstchain/docs/api/lstchain.image.modifier.tune_nsb_on_waveform.rst: WARNING: document isn't included in any toctree
/Users/dmorcuende/Software/CTA/LST/cta-lstchain/docs/api/lstchain.io.io.parse_cfg_bytestring.rst: WARNING: document isn't included in any toctree
/Users/dmorcuende/Software/CTA/LST/cta-lstchain/docs/notebooks.rst: WARNING: document isn't included in any toctree

[morcuended]

I realized that most of these warnings come from old previously built documentation. With a clean building, there is only one warning remaining:

/Users/dmorcuende/Software/CTA/LST/cta-lstchain/docs/notebooks.rst: WARNING: document isn't included in any toctree

that will be included in PR #1091.

Closing this.