docs: parse-headers.rst: remove uneeded parenthesis

As pointed by Randy, the parenthesis there is not needed and it
violates the document coding style.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/linux-doc/9d709020-03fe-467c-be7f-d5ee251bb79a@infradead.org/
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <e5de9f7b1f6a963b2912574a65495c47cfbb13ba.1762878176.git.mchehab+huawei@kernel.org>

Author: mchehab

Documentation/doc-guide/parse-headers.rst

@@ -89,7 +89,7 @@ defines the C namespace to be used.
 It is meant to allow having more comprehensive documentation, where
 uAPI headers will create cross-reference links to the code.
 
-The output is written at the (``FILE_OUT``).
+The output is written at the ``FILE_OUT``.
 
 The ``FILE_RULES`` may contain contain three types of statements:
 **ignore**, **replace** and **namespace**.