docs: fix changelog page heading levels and sidebar

Give the changelog page its own title so version headings become
sections: the current version now appears in the page ToC at the same
level as older versions. Fold the changelog link into the Development
sidebar section and use :titlesonly: to keep version headings out of
the sidebar. Exclude docs/changelog.rst from docstrfmt, which rewrote
the title to the same level as the included CHANGELOG.rst headings.

Assisted-by: ClaudeCode:claude-fable-5
Claude-Session: https://claude.ai/code/session_018JS2hRNjfymjCZez1jvGVV

Author: henryiii

.pre-commit-config.yaml

@@ -44,7 +44,9 @@ repos:
       - id: docstrfmt
         args: ["-l", "120"]
         additional_dependencies: ["sphinx>=9.1"]
-        exclude: ^docs/index\.rst$ # https://github.com/LilSpazJoekp/docstrfmt/issues/176
+        # index: https://github.com/LilSpazJoekp/docstrfmt/issues/176
+        # changelog: title must outrank the included CHANGELOG.rst headings
+        exclude: ^docs/(index|changelog)\.rst$
   - repo: https://github.com/astral-sh/ruff-pre-commit
     rev: 65dbdb59d2f2d9c3bdc343c566821ad3319ddaa3 # frozen: v0.16.3
     hooks:

docs/changelog.rst

@@ -1 +1,5 @@
+===========
+ Changelog
+===========
+
 .. include:: ../CHANGELOG.rst

docs/index.rst

@@ -91,19 +91,15 @@ Where to start
 
 .. toctree::
    :caption: Development
+   :titlesonly:
    :hidden:
 
    development/contributing
    development/release
+   changelog
    Source Code <https://github.com/pypa/build/>
    Issue Tracker <https://github.com/pypa/build/issues>
 
-.. toctree::
-   :caption: Changelog
-   :hidden:
-
-   changelog
-
 .. _pip: https://github.com/pypa/pip
 .. _PyPI: https://pypi.org/
 .. _pipx: https://github.com/pipxproject/pipx