Update pytorch_sphinx_theme2 version to 0.4.6 (#177616)

Update pytorch_sphinx_theme2 version to 0.4.6 (#177562)

Changelog here: https://github.com/pytorch/pytorch_sphinx_theme/blob/pytorch_sphinx_theme2/CHANGELOG.md

Pull Request resolved: #177562
Approved by: https://github.com/AlannaBurke, https://github.com/albanD

(cherry picked from commit c5dcefd)

Co-authored-by: Svetlana Karslioglu <svekars@meta.com>

Author: pytorchbot

.ci/docker/requirements-docs.txt

@@ -2,9 +2,9 @@ sphinx==7.2.6
 #Description: This is used to generate PyTorch docs
 #Pinned versions: 7.2.6
 
-pytorch_sphinx_theme2==0.4.3
+pytorch_sphinx_theme2==0.4.6
 #Description: This is needed to generate PyTorch docs
-#Pinned versions: 0.4.3
+#Pinned versions: 0.4.6
 
 # TODO: sphinxcontrib.katex 0.9.0 adds a local KaTeX server to speed up pre-rendering
 # but it doesn't seem to work and hangs around idly. The initial thought that it is probably