doc(dev): reST/sphinx add tabbed views extension (sphinx_tabs.tabs)

See issue #1785:

  idea: in the doc, provide installation instructions with one tab per
  distrubution

preview (don't bookmark):

  https://return42.github.io/searx/dev/reST.html#tabbed-views

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

docs/conf.py

@@ -60,6 +60,7 @@ extensions = [
     "sphinxcontrib.jinja",  # https://github.com/tardyp/sphinx-jinja
     'linuxdoc.rstFlatTable',    # Implementation of the 'flat-table' reST-directive.
     'linuxdoc.kfigure',         # Sphinx extension which implements scalable image handling.
+    "sphinx_tabs.tabs", # https://github.com/djungelorm/sphinx-tabs
 ]
 
 intersphinx_mapping = {

docs/dev/reST.rst

@@ -1148,6 +1148,81 @@ points to the name space of the python module: ``webapp``.
    }
 
 
+Tabbed views
+============
+
+.. _sphinx-tabs: https://github.com/djungelorm/sphinx-tabs
+.. _basic-tabs: https://github.com/djungelorm/sphinx-tabs#basic-tabs
+.. _group-tabs: https://github.com/djungelorm/sphinx-tabs#group-tabs
+.. _code-tabs: https://github.com/djungelorm/sphinx-tabs#code-tabs
+
+With `sphinx-tabs`_ extension we have *tabbed views*.  To provide installation
+instructions with one tab per distribution we use the `group-tabs`_ directive,
+others are basic-tabs_ and code-tabs_.
+
+
+.. code:: reST
+
+   .. tabs::
+
+      .. group-tab:: Linux
+
+         Linux Line 1
+
+      .. group-tab:: Mac OSX
+
+         Mac OSX Line 1
+
+      .. group-tab:: Windows
+
+         Windows Line 1
+
+   .. tabs::
+
+      .. group-tab:: Linux
+
+         Linux Line 1
+
+      .. group-tab:: Mac OSX
+
+         Mac OSX Line 1
+
+      .. group-tab:: Windows
+
+         Windows Line 1
+
+
+.. admonition:: Tabbed view (grouped)
+   :class: rst-example
+
+   .. tabs::
+
+      .. group-tab:: Linux
+
+         Linux Line 1
+
+      .. group-tab:: Mac OSX
+
+         Mac OSX Line 1
+
+      .. group-tab:: Windows
+
+         Windows Line 1
+
+   .. tabs::
+
+      .. group-tab:: Linux
+
+         Linux Line 1
+
+      .. group-tab:: Mac OSX
+
+         Mac OSX Line 1
+
+      .. group-tab:: Windows
+
+         Windows Line 1
+
 
 .. _KISS: https://en.wikipedia.org/wiki/KISS_principle
 

requirements-dev.txt

@@ -13,3 +13,4 @@ zope.testrunner==4.5.1
 selenium==3.141.0
 linuxdoc @ git+http://github.com/return42/linuxdoc.git
 sphinx-jinja
+sphinx-tabs