Documentation: Drop local table of contents from introduction

The local table of contents from the introduction page doesn't provide
much navigation value as the page is short. It also stands out, as no
other page has a local table of contents. Drop it, we will reintroduce
local tables of contents more globally if needed later.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>

Documentation/introduction.rst

@@ -1,8 +1,5 @@
 .. SPDX-License-Identifier: CC-BY-SA-4.0
 
-.. contents::
-   :local:
-
 .. include:: documentation-contents.rst
 
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