[docs] all: Switch to sphinx-readthedocs-theme

From https://github.com/readthedocs/sphinx_rtd_theme

.github/workflows/build.yml

@@ -179,7 +179,7 @@ jobs:
         sudo apt-get update
     - name: Install docs dependencies
       run: |
-        sudo apt-get install python3-sphinx
+        sudo apt-get install python3-sphinx python3-sphinx-rtd-theme
         sudo pip3 install sphinxcontrib-spelling
     - name: Build docs
       run: |

README.md

@@ -19,4 +19,4 @@ https://looking-glass.io/downloads
 Source code for the documentation can be found in the `/doc` directory.
 
 You may view this locally as HTML by running `make html` with `python3-sphinx`
-installed.
+and `python3-sphinx-rtd-theme` installed.

doc/conf.py

@@ -47,6 +47,7 @@ rst_prolog = """
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = [
+    'sphinx_rtd_theme',
 ]
 
 try:
@@ -81,11 +82,11 @@ master_doc = 'index'
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-html_theme = 'alabaster'
+html_theme = 'sphinx_rtd_theme'
 
 html_theme_options = {
-    'logo': 'icon-128x128.png',
-    'fixed_sidebar': 'true',
+    'logo_only': True,
+    'style_nav_header_background': 'transparent',
 }
 
 html_sidebars = {
@@ -99,7 +100,9 @@ html_sidebars = {
 
 html_favicon = '../resources/icon.ico'
 
+html_logo = '../resources/icon-128x128.png'
+
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['../resources/icon-128x128.png']
+html_static_path = []