docs: parse-headers.rst: Fix a typo

Replace "vantage" with "advantage" in the description of userspace API
cross-references.

Signed-off-by: Ankit Khushwaha <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>
Message-ID: <[e-mail]>

Documentation/doc-guide/parse-headers.rst

···
 Sometimes, it is useful to include header files and C example codes in
 order to describe the userspace API and to generate cross-references
 between the code and the documentation. Adding cross-references for
-userspace API files has an additional vantage: Sphinx will generate warnings
+userspace API files has an additional advantage: Sphinx will generate warnings
 if a symbol is not found at the documentation. That helps to keep the
 uAPI documentation in sync with the Kernel changes.
 The :ref:`parse_headers.py <parse_headers>` provides a way to generate such