kernel-doc: Added "*" in $type_constants2 to fix 'make htmldocs' warning.

Fixed: WARNING: Inline literal start-string without end-string in
Documentation/core-api/workqueue.rst

Added "*" in $type_constants2 in kernel-doc script to include "*" in the
conversion to hightlights.
Previously: %WQ_* -->  ``WQ_``*
After Changes: %WQ_* -->  ``WQ_*``
Need for the fix: ``* is not recognized as a valid end-string for inline
literal.

Link: https://lore.kernel.org/linux-doc/640114d2-5780-48c3-a294-c0eba230f984@gmail.com


Signed-off-by: Utkarsh Tripathi <utripathi2002@gmail.com>
Suggested-by: Akira Yokosawa <akiyks@gmail.com>
Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Link: https://lore.kernel.org/r/20240503182650.7761-1-utripathi2002@gmail.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>