doc: notes: use stuck form throughout

gitcli(7) recommends the *stuck form*.  `--ref` is the only one which
does not use it.

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

Documentation/git-notes.adoc

@@ -200,7 +200,7 @@ order of similar options. For example, for `-C <object> -m<message>`,
 previous `-C`. This is a known limitation that may be fixed in the
 future.
 
-`--ref <ref>`::
+`--ref=<ref>`::
 	Manipulate the notes tree in _<ref>_.  This overrides
 	`GIT_NOTES_REF` and the `core.notesRef` configuration.  The ref
 	specifies the full refname when it begins with `refs/notes/`; when it