Bug 1536059 - change checkbox attribute inheritance order to make label accesskey formatting work, r=bgrins

Differential Revision: https://phabricator.services.mozilla.com/D23885

--HG--
extra : moz-landing-system : lando

toolkit/content/widgets/checkbox.js

@@ -30,7 +30,7 @@ class MozCheckbox extends MozElements.BaseText {
 
   static get inheritedAttributes() {
     return {
-      ".checkbox-label": "accesskey,text=label",
+      ".checkbox-label": "text=label,accesskey",
       ".checkbox-icon": "src",
     };
   }