Improve the documentation.

* Add code block `copy` button via `sphinx_copybutton`
* Change permalink icon

PiperOrigin-RevId: 492955205
Change-Id: I2bcebcf7dd1fcace26ba03a4e348cb46eb838b57

doc/conf.py

@@ -44,6 +44,7 @@ master_doc = 'index'
 extensions = [
     'sphinxcontrib.katex',
     'sphinxcontrib.youtube',
+    "sphinx_copybutton",
     'sphinx_reredirects',
     'sphinx_toolbox.collapse',
     "mujoco_include",
@@ -122,7 +123,8 @@ html_theme_options = {
 }
 
 for v in html_theme_options.values():
-  v.update(SHARED_CSS_VARIABLES)
+  if isinstance(v, dict):
+    v.update(SHARED_CSS_VARIABLES)
 
 pygments_style = "default"
 pygments_dark_style = "monokai"
@@ -141,6 +143,8 @@ html_css_files = [
 
 html_favicon = 'favicons/favicon-32x32.png'
 
+html_permalinks_icon = "🔗"
+
 # -- Options for katex ------------------------------------------------------
 
 # See: https://sphinxcontrib-katex.readthedocs.io/en/0.4.1/macros.html

doc/requirements.txt

@@ -2,6 +2,7 @@ Sphinx==4.5.0
 furo==2022.9.29
 sphinxcontrib-katex==0.8.6
 sphinxcontrib-youtube==1.1.0
+sphinx-copybutton==0.5.1
 sphinx-reredirects==0.0.1
 sphinx-toolbox==3.2.0
 nbsphinx==0.8.0