[doc] engine tables: show engines in all categories

Previously the documentation grouped the engines by their first
category so e.g. YouTube and Invidious were only shown in the
in the videos section but not in the music section.

This commit fixes this by iterating over searx.engines.categories,
which also has the added benefit that the sections are now in the
same order as the tabs in the user interface.

docs/admin/engines/configured_engines.rst

@@ -16,7 +16,7 @@ Explanation of the :ref:`general engine configuration` shown in the table
 
    SearXNG supports {{engines | length}} search engines (of which {{enabled_engine_count}} are enabled by default).
 
-   {% for category, engines in engines.items() | groupby('1.categories.0') %}
+   {% for category, engines in categories.items() %}
 
    {{category}} search engines
    ---------------------------------------
@@ -39,9 +39,9 @@ Explanation of the :ref:`general engine configuration` shown in the table
         - Safe search
         - Time range
 
-      {% for name, mod in engines | sort_engines %}
+      {% for mod in engines | sort_engines %}
 
-      * - `{{name}} <{{mod.about and mod.about.website}}>`_
+      * - `{{mod.name}} <{{mod.about and mod.about.website}}>`_
         - ``!{{mod.shortcut}}``
         - {%- if 'searx.engines.' + mod.__name__ in documented_modules %}
           :py:mod:`~searx.engines.{{mod.__name__}}`

docs/conf.py

@@ -40,6 +40,7 @@ exclude_patterns = ['build-templates/*.rst']
 import searx.engines
 import searx.plugins
 searx.engines.load_engines(searx.settings['engines'])
+
 jinja_contexts = {
     'searx': {
         'engines': searx.engines.engines,
@@ -48,13 +49,14 @@ jinja_contexts = {
             'node': os.getenv('NODE_MINIMUM_VERSION')
         },
         'enabled_engine_count': sum(not x.disabled for x in searx.engines.engines.values()),
+        'categories': searx.engines.categories,
     },
 }
 jinja_filters = {
     'sort_engines':
     lambda engines: sorted(
         engines,
-        key=lambda engine: (engine[1].about.get('language', ''), engine[0])
+        key=lambda engine: (engine.about.get('language', ''), engine.name)
     )
 }