Add high-res readthedocs favicons for iOS and Android.

PiperOrigin-RevId: 520324992
Change-Id: If22c228eee50570c63357f08b8cd1eab2fab55f8

doc/conf.py

@@ -45,6 +45,7 @@ extensions = [
     'sphinxcontrib.katex',
     'sphinxcontrib.youtube',
     'sphinx_copybutton',
+    'sphinx_favicon',
     'sphinx_reredirects',
     'sphinx_toolbox.collapse',
     'mujoco_include',
@@ -149,7 +150,29 @@ html_css_files = [
     'theme_overrides.css',
 ]
 
-html_favicon = 'favicons/favicon-32x32.png'
+favicons = [
+    {
+        'sizes': '16x16',
+        'href': 'favicons/favicon-16x16.png',
+    },
+    {
+        'sizes': '32x32',
+        'href': 'favicons/favicon-32x32.png',
+    },
+    {
+        'rel': 'apple-touch-icon',
+        'sizes': '180x180',
+        'href': 'favicons/favicon-180x180.png',
+    },
+    {
+        'sizes': '180x180',
+        'href': 'favicons/favicon-180x180.png',
+    },
+    {
+        'sizes': '192x192',
+        'href': 'favicons/favicon-192x192.png',
+    },
+]
 
 # -- Options for katex ------------------------------------------------------
 

doc/requirements.txt

@@ -3,6 +3,7 @@ furo==2022.9.29
 sphinxcontrib-katex==0.8.6
 sphinxcontrib-youtube==1.1.0
 sphinx-copybutton==0.5.1
+sphinx-favicon==1.0.1
 sphinx-reredirects==0.0.1
 sphinx-toolbox==3.2.0
 nbsphinx==0.8.0