[furo] remove .. contents:: directives (#3408)

The directive creates a table of contents for the page.  However, Furo includes
a table of contents already in the sidebar.  It is, thus, recommended to
removing the `.. contents::` directive.

[1] https://github.com/pradyunsg/furo/issues/88#issuecomment-803297274

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

docs/dev/engines/offline/command-line-engines.rst

@@ -9,11 +9,6 @@ Command Line Engines
    - :origin:`command.py <searx/engines/command.py>`
    - :ref:`offline engines`
 
-.. contents::
-   :depth: 2
-   :local:
-   :backlinks: entry
-
 .. sidebar:: info
 
    Initial sponsored by `Search and Discovery Fund

docs/dev/engines/offline/nosql-engines.rst

@@ -10,11 +10,6 @@ NoSQL databases
    - `valkey.io <https://valkey.io/>`_
    - `MongoDB <https://www.mongodb.com>`_
 
-.. contents::
-   :depth: 2
-   :local:
-   :backlinks: entry
-
 .. sidebar:: info
 
    Initial sponsored by `Search and Discovery Fund

docs/dev/engines/offline/search-indexer-engines.rst

@@ -7,11 +7,6 @@ Local Search APIs
    - `Comparison to alternatives
      <https://docs.meilisearch.com/learn/what_is_meilisearch/comparison_to_alternatives.html>`_
 
-.. contents::
-   :depth: 1
-   :local:
-   :backlinks: entry
-
 .. sidebar:: info
 
    Initial sponsored by `Search and Discovery Fund

docs/dev/engines/offline/sql-engines.rst

@@ -10,11 +10,6 @@ SQL Engines
    - `PostgreSQL <https://www.postgresql.org>`_
    - `MySQL <https://www.mysql.com>`_
 
-.. contents::
-   :depth: 2
-   :local:
-   :backlinks: entry
-
 .. sidebar:: info
 
    Initial sponsored by `Search and Discovery Fund