doc: proofread of the all reST sources (no content change)

Normalize reST sources with best practice and KISS in mind.

to name a few points:

- simplify reST tables
- make use of ``literal`` markup for monospace rendering
- fix code-blocks for better rendering in HTML
- normalize section header markup
- limit all lines to a maximum of 79 characters
- add option -H to the sudo command used in code blocks
- drop useless indentation of lists
- ...

[1] https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html

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

docs/admin/morty.rst

@@ -1,21 +1,26 @@
+=========================
 How to setup result proxy
 =========================
 
-By default searx can only act as an image proxy for result images,
-but it is possible to proxify all the result URLs with an external service,
-`morty <https://github.com/asciimoo/morty>`__.
+.. _morty: https://github.com/asciimoo/morty
+.. _morty's README: https://github.com/asciimoo/morty
 
-To use this feature, morty has to be installed and activated in searx's ``settings.yml``.
+By default searx can only act as an image proxy for result images, but it is
+possible to proxify all the result URLs with an external service, morty_.
+
+To use this feature, morty has to be installed and activated in searx's
+``settings.yml``.
 
 Add the following snippet to your ``settings.yml`` and restart searx:
 
-
 .. code:: yaml
 
     result_proxy:
         url : http://127.0.0.1:3000/
         key : your_morty_proxy_key
 
-``url`` is the address of the running morty service
+``url``
+  Is the address of the running morty service.
 
-``key`` is an optional argument, see `morty's README <https://github.com/asciimoo/morty>`__ for more information.
+``key``
+  Is an optional argument, see `morty's README`_ for more information.