Bug 1617608 - Allow toggling :focus-visible from inspector. r=rcaliman

Differential Revision: https://phabricator.services.mozilla.com/D97164

devtools/client/inspector/rules/test/browser_rules_pseudo_lock_options.js

@@ -26,6 +26,9 @@ const TEST_URI = `
     div:visited {
       color: orange;
     }
+    div:focus-visible {
+      color: wheat;
+    }
   </style>
   <div>test div</div>
 `;

devtools/shared/css/constants.js

@@ -32,6 +32,7 @@ exports.PSEUDO_CLASSES = [
   ":hover",
   ":active",
   ":focus",
+  ":focus-visible",
   ":focus-within",
   ":visited",
 ];