Bug 1556539 - Move rules unneeded in content from minimal-xul.css to xul.css r=NeilDeakin

Differential Revision: https://phabricator.services.mozilla.com/D33550

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

toolkit/content/minimal-xul.css

@@ -27,15 +27,6 @@
   box-sizing: border-box;
 }
 
-:root {
-  text-rendering: optimizeLegibility;
-  -moz-control-character-visibility: visible;
-}
-
-:root:-moz-locale-dir(rtl) {
-  direction: rtl;
-}
-
 /* hide the content and destroy the frame */
 [hidden="true"] {
   display: none;

toolkit/content/xul.css

@@ -26,9 +26,15 @@
 @namespace xbl url("http://www.mozilla.org/xbl"); /* namespace for XBL elements */
 
 :root {
+  text-rendering: optimizeLegibility;
+  -moz-control-character-visibility: visible;
   --animation-easing-function: cubic-bezier(.07, .95, 0, 1);
 }
 
+:root:-moz-locale-dir(rtl) {
+  direction: rtl;
+}
+
 /* ::::::::::
    :: Rules for 'hiding' portions of the chrome for special
    :: kinds of windows (not JUST browser windows) with toolbars