docs(functions): drop backticks from doc-headers

CONTRIBUTING states doc-headers are written as plain text -- the header
is read as-is by config-help, by funcsave, and by anyone opening the
file, and docs/codespans.py adds the site's inline code spans at render
time. 22 files had drifted from that, carrying 41 hand-written spans
that reached config-help and the man page as literal backtick
characters inside an otherwise verbatim block.

The one span whose content ended in a space is requoted rather than
dropped, so "read> " keeps reading as a prompt string.

functions/__kitty_logging_has_watcher.fish

@@ -6,7 +6,7 @@
 #
 # DESCRIPTION
 #   Succeeds (returns 0) when the top-level kitty.conf contains an active
-#   (non-commented) `watcher` directive — whether the fish-config managed one or
+#   (non-commented) watcher directive — whether the fish-config managed one or
 #   a user's own. Used to suppress the setup reminder and to inform status.
 #
 # EXIT STATUS