rc tools git: quote $kak_buffile for add/rm

Our "git add" and "git rm" default to the current file.  The shell
interprets globs in the filename, which can lead to surprising results,
for example if it's accidentally used on a scratch buffer like *git*.

rc/tools/git.kak

@@ -713,7 +713,7 @@ define-command -params 1.. \
         add|rm)
             cmd="$1"
             shift
-            run_git_cmd $cmd "${@:-${kak_buffile}}"
+            run_git_cmd $cmd "${@:-"${kak_buffile}"}"
             ;;
         reset|checkout)
             run_git_cmd "$@"