Remove a stale comment.

The visualbell popup no longer clears the command-line.

--HG--
extra : rebase_source : 0b661f2b1ff98eda15cf531aa060b54a7e8bf600

common/content/dactyl.js

@@ -124,7 +124,6 @@ const Dactyl = Module("dactyl", {
      * 'visualbell' option.
      */
     beep: requiresMainThread(function () {
-        // FIXME: popups clear the command line
         if (options["visualbell"]) {
             // flash the visual bell
             let popup = document.getElementById("dactyl-visualbell");