Readme: remove outdated text about building on rtd
Readme: remove outdated text about building on rtd
mitya57/sphinx_rtd_theme,mitya57/sphinx_rtd_theme,snide/sphinx_rtd_theme,snide/sphinx_rtd_theme,snide/sphinx_rtd_theme,mitya57/sphinx_rtd_theme,snide/sphinx_rtd_theme,mitya57/sphinx_rtd_theme