Fix RST syntax errors in README and add twine check to CI

Fix malformed changelog entries (missing bullet markers, typo in heading)
that caused twine check to fail. Add a twine check step to the sdist build
job so markup issues are caught before publishing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: whtsky

.github/workflows/build.yml

@@ -41,6 +41,8 @@ jobs:
         persist-credentials: false
     - name: Build SDist
       run: pipx run build --sdist
+    - name: Check distribution
+      run: pipx run twine check dist/*
     - uses: actions/upload-artifact@v6
       with:
         name: sdist

README.rst

@@ -43,14 +43,17 @@ ChangeLog
 
 Version 3.0.2
 ~~~~~~~~~~~~~~~
- Drop support for Python 3.6–3.9, require Python >= 3.10
- Add support for Python 3.12 & 3.13
- Fix Cython 3 build
+
++ Drop support for Python 3.6–3.9, require Python >= 3.10
++ Add support for Python 3.12 & 3.13
++ Fix Cython 3 build
 
 Version 3.0.1
 ~~~~~~~~~~~~~~~
- Add support for Python 3.11
-Versoin 3.0.0
+
++ Add support for Python 3.11
+
+Version 3.0.0
 ~~~~~~~~~~~~~~~
 
 + Add support for Python 3.9 & 3.10