kernel-doc: allow object-like macros in ReST output

kernel-doc: allow object-like macros in ReST output

output_function_rst() does not handle object-like macros. It presents
a trailing "()" while output_function_man() handles these macros
correctly.

Update output_function_rst() to handle object-like macros.
Don't show the "Parameters" heading if there are no parameters.

For output_function_man(), don't show the "ARGUMENTS" heading if there
are no parameters.

I have tested this quite a bit with my ad hoc test files for both ReST
and man format outputs. The generated output looks good.

Fixes: cbb4d3e6510b ("scripts/kernel-doc: handle object-like macros")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Horia Geanta <horia.geanta@freescale.com>
Tested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241015181107.536894-1-rdunlap@infradead.org