Fix note highlight being added to new notes

Always use a explicit true/false value to set highlight because jQuery
assumes `null` means toggle from whatever state and doesn't force false.

Regressed in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/12098

app/assets/javascripts/notes.js

@@ -322,7 +322,9 @@ const normalizeNewlines = function(str) {
 
     Notes.updateNoteTargetSelector = function($note) {
       const hash = gl.utils.getLocationHash();
-      $note.toggleClass('target', hash && $note.filter(`#${hash}`).length > 0);
+      // Needs to be an explicit true/false for the jQuery `toggleClass(force)`
+      const addTargetClass = Boolean(hash && $note.filter(`#${hash}`).length > 0);
+      $note.toggleClass('target', addTargetClass);
     };
 
     /*

spec/javascripts/notes_spec.js

@@ -176,7 +176,7 @@ import '~/notes';
 
         Notes.updateNoteTargetSelector($note);
 
-        expect($note.toggleClass).toHaveBeenCalledWith('target', null);
+        expect($note.toggleClass).toHaveBeenCalledWith('target', false);
       });
     });