Bug 1573791 - Fix Accessibility tabs dropdown checkmark for RTL users r=yzen

Differential Revision: https://phabricator.services.mozilla.com/D42220

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

devtools/client/themes/tooltips.css

@@ -440,7 +440,7 @@ strong {
   background-position: center left 7px;
 }
 
-.tooltip-container[type="doorhanger"] .menuitem > .command[aria-checked="true"]:-moz-locale-dir(rtl) {
+.tooltip-container[type="doorhanger"] .menuitem > .command[aria-checked="true"]:dir(rtl) {
   background-position: center right 7px;
 }