char.h: fix gtk-doc comment style

Fix up conformance to GTK-Doc function comment style, as documented in
https://developer.gnome.org/gtk-doc-manual/stable/documenting_symbols.html.en

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
2 files changed