docs: kdoc_output: don't add a man page tail for filtered-out symbolsdocs-nextdocs-mw

ManFormat.msg() appends the "SEE ALSO" tail after every call to the base
class msg(), even when the -e, -i, -s or --nosymbol filters dropped the
symbol and nothing was written for it. With -s, every other symbol in
the file leaves a stray "SEE ALSO" block behind the requested page. With
-e on a file that exports nothing, the output is only such blocks, with
no .TH header at all:

  $ tools/docs/kernel-doc -man -s string_get_size lib/string_helpers.c \
      | grep -c 'SEE ALSO'
  13
  $ tools/docs/kernel-doc -man -e include/rdma/ib_mad.h | grep -c '^\.TH'
  0

Only add the tail when the base class produced a page, and add unit
tests for both cases.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/all/fc7978bb-a71f-456d-84bb-670c8f0426ed@infradead.org/
Fixes: 104e0a682e12 ("tools: kernel-doc: add a see also section at man pages")
Assisted-by: LLM
Signed-off-by: Simon Sudarushkin <simonsudarushkin@gmail.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260929-kdoc-man-filter-v1-1-5f70268885d1@gmail.com>

0 files changed, 0 insertions, 0 deletions