Fix docs links (#8160)

PR #7886 introduced this link to docs.rs for the docs of the public
APIs: https://docs.rs/releases/search?query=zebra. However, the query in
the link returns crates that are not part of the Zebra's public API,
and doesn't return the two tower-* crates that are part of Zebra.

This commit refers to a manually created list of links pointing to the
docs of the public APIs of all current Zebra crates.

README.md

@@ -191,11 +191,12 @@ The Zcash Foundation maintains the following resources documenting Zebra:
   - [User Documentation](https://zebra.zfnd.org/user.html),
   - [Developer Documentation](https://zebra.zfnd.org/dev.html).
 
-- The public APIs for the latest releases of the individual `zebra-*` crates are documented at
-[docs.rs](https://docs.rs/releases/search?query=zebrad).
+- The [documentation of the public
+  APIs](https://docs.rs/zebrad/latest/zebrad/#zebra-crates) for the latest
+  releases of the individual Zebra crates.
 
-- The internal APIs for the `main` branch are documented at
-<https://doc-internal.zebra.zfnd.org>.
+- The [documentation of the internal APIs](https://doc-internal.zebra.zfnd.org)
+  for the `main` branch of the whole Zebra monorepo.
 
 ## User support
 

book/src/api.md

@@ -1,8 +1,10 @@
 # API Reference
 
-Zebra's API documentation is generated using Rustdoc:
+The Zcash Foundation maintains the following API documentation for Zebra:
 
-- [`docs.rs`](https://docs.rs/releases/search?query=zebrad) renders documentation for the public API
-  of the latest crate releases;
-- [`doc-internal.zebra.zfnd.org`](https://doc-internal.zebra.zfnd.org/) renders documentation for
-  the internal API on the `main` branch.
+- The [documentation of the public
+  APIs](https://docs.rs/zebrad/latest/zebrad/#zebra-crates) for the latest
+  releases of the individual Zebra crates.
+
+- The [documentation of the internal APIs](https://doc-internal.zebra.zfnd.org)
+  for the `main` branch of the whole Zebra monorepo.

book/src/dev.md

@@ -1,9 +1,11 @@
 # Developer Documentation
 
-This section contains the contribution guide and design documentation. It
-does not contain API documentation, which is generated using Rustdoc:
+This section contains the contribution guide and design documentation. It does
+not contain:
 
-- [`docs.rs`](https://docs.rs/releases/search?query=zebrad) renders documentation for the public API
-  of the latest crate releases;
-- [`doc-internal.zebra.zfnd.org`](https://doc-internal.zebra.zfnd.org/) renders documentation for
-  the internal API on the `main` branch.
+- The [documentation of the public
+  APIs](https://docs.rs/zebrad/latest/zebrad/#zebra-crates) for the latest
+  releases of the individual Zebra crates.
+
+- The [documentation of the internal APIs](https://doc-internal.zebra.zfnd.org)
+  for the `main` branch of the whole Zebra monorepo.