[3.8] gh-114021: Pin various sphinxcontrib extensions to older versions (GH-114022)

Doc/constraints.txt

@@ -0,0 +1,24 @@
+# We have upper bounds on our transitive dependencies here
+# To avoid new releases unexpectedly breaking our build.
+# This file can be updated on an ad-hoc basis,
+# though it will probably have to be updated
+# whenever Doc/requirements.txt is updated.
+
+# Direct dependencies of Sphinx
+babel<3
+colorama<0.5
+imagesize<1.5
+Jinja2<3.2
+packaging<24
+Pygments>=2.16.1,<3
+requests<3
+snowballstemmer<3
+sphinxcontrib-applehelp<1.0.5
+sphinxcontrib-devhelp<1.0.6
+sphinxcontrib-htmlhelp<2.0.5
+sphinxcontrib-jsmath<1.1
+sphinxcontrib-qthelp<1.0.7
+sphinxcontrib-serializinghtml<1.1.10
+
+# Direct dependencies of Jinja2 (Jinja is a dependency of Sphinx, see above)
+MarkupSafe<2.2

Doc/requirements.txt

@@ -18,3 +18,5 @@ blurb
 # The theme used by the documentation is stored separately, so we need
 # to install that as well.
 python-docs-theme
+
+-c constraints.txt