doc: hook: don’t self-link via config include

doc: hook: don’t self-link via config include

Do not link to git-hook(1) from the config options when we already are
in that doc.

This implementation is similar to the updates to git-init(1) and
git-commit(1), implemented in [1] and [2], respectively.

† 1: e7b3a768 (doc: git-init: rework config item init.templateDir,
     2024-03-10)
† 2: 819fdd6e (doc: convert git commit config to new format, 2025-01-15)

Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>