docs: use list for readablitily

Co-authored-by: Michal Sniatala <michal@sniatala.pl>

user_guide_src/source/installation/upgrade_4xx.rst

@@ -170,17 +170,14 @@ Error Handling
 
 - The behavior in CI4 has been slightly changed.
 
-  - In CI3, ignored errors by ``error_reporting()`` in **index.php** are not logged,
-    but other errors are logged (but depending on the ``log_threshold`` setting,
-    they may not be written to the log file). Only errors with the error level
-    ``E_ERROR | E_PARSE | E_COMPILE_ERROR | E_CORE_ERROR | E_USER_ERROR``
-    will stop the framework processing, regardless of the error level set in
-    ``error_reporting()``.
-  - In CI4, only errors with the error level set by ``error_reporting()`` in
-    **app/Config/Boot/{environment}.php** are logged (but depending on the
-    ``Config\Logger::$threshold`` setting, they may not be written to the log file).
-    All errors that are not ignored by ``error_reporting()`` will stop the
-    framework processing.
+  - In CI3 the behavior was set in the **index.php** file:
+      - errors ignored by ``error_reporting()`` was not logged;
+      - other errors were logged (depending on the settings in ``log_threshold``, they may not have been written to the log file);
+      - errors with an error level of ``E_ERROR | E_PARSE | E_COMPILE_ERROR | E_CORE_ERROR | E_USER_ERROR`` stopped framework processing, regardless of the error level set in ``error_reporting()``;
+  - In CI4, the behavior is set in the **app/Config/Boot/{environment}.php** file:
+      - errors with the error level set by ``error_reporting()`` are logged (but depending on the
+    ``Config\Logger::$threshold`` setting, they may not be written to the log file);
+      - all errors that are not ignored by ``error_reporting()`` will stop the framework processing;
 
 Extending the Framework
 =======================