Adding Sphinx requirements.txt.

Author: AlannaBurke

docs/requirements.txt

@@ -0,0 +1,11 @@
+sphinx==7.2.6
+-e git+https://github.com/pytorch/pytorch_sphinx_theme.git@pytorch_sphinx_theme2#egg=pytorch_sphinx_theme2
+sphinxcontrib.katex==0.9.10
+breathe==4.34.0  # only if generating C++
+exhale==0.2.3  # only if generating C++ docs
+docutils==>=0.18.1,<0.21
+sphinx-design==0.6.1
+sphinxcontrib-mermaid==1.0.0
+myst-parser==0.18.1  # if want to contribute in markdown
+sphinx-gallery==0.14.0  # only if hosting interactive tutorials
+sphinx-sitemap==2.7.1