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/fish-deps.fish

@@ -29,10 +29,10 @@
 #     Optional            btop, dust, duf, prettyping, go, lazygit,
 #                         lazydocker, docker, yt-dlp, screen — single-purpose
 #                         wrapper conveniences that only matter if you
-#                         already use that tool; skipped by `install`/`sync`
+#                         already use that tool; skipped by install/sync
 #                         unless --optional (or --all) is passed
 #     Terminal Emulators  kitty, wezterm — only matter if one of them is
-#                         your actual terminal; skipped by `install`/`sync`
+#                         your actual terminal; skipped by install/sync
 #                         unless --terminals (or --all) is passed
 #     Integrations        wakatime, tailscale
 #