Include rst files in docs in sdist. Fixes #2477.

MANIFEST.in

 recursive-include setuptools *.py *.exe *.xml
 recursive-include tests *.py
 recursive-include setuptools/tests *.html
-recursive-include docs *.py *.txt *.conf *.css *.css_t Makefile indexsidebar.html
+recursive-include docs *.py *.txt *.rst *.conf *.css *.css_t Makefile indexsidebar.html
 recursive-include setuptools/_vendor *.py *.txt
 recursive-include pkg_resources *.py *.txt
 recursive-include pkg_resources/tests/data *

changelog.d/2477.misc.rst

+Restore inclusion of rst files in sdist.