Bump sphinx to fix missing parenthesis when argument is a tuple.

See: python/cpython#93108

Author: JulienPalard

build_docs.py

@@ -211,7 +211,7 @@ def __gt__(self, other):
         "3.10",
         branch="origin/3.10",
         status="stable",
-        sphinx_version="3.2.1",
+        sphinx_version="3.4.3",
     ),
     Version(
         "3.9",
@@ -959,6 +959,7 @@ def dev_symlink(www_root: Path, group):
     for language in LANGUAGES:
         symlink(www_root, language, current_dev, "dev", group)
 
+
 def proofread_canonicals(www_root: Path) -> None:
     """In www_root we check that all canonical links point to existing contents.