Bug 1527197 - Fix background images in RTL mode in the new "about:config" page. r=ntim

Differential Revision: https://phabricator.services.mozilla.com/D20135

--HG--
extra : rebase_source : 598e0477056700d61054fee976050abee0c0edd0

browser/components/aboutconfig/content/aboutconfig.css

@@ -42,10 +42,14 @@ body.config-warning {
   background-repeat: no-repeat;
   background-position: 9px center;
   background-size: 12px 12px;
-  padding-left: 30px;
+  padding-inline-start: 30px;
   z-index: 1;
 }
 
+#about-config-search:dir(rtl) {
+  background-position-x: right 9px;
+}
+
 #prefs {
   background-color: var(--in-content-box-background);
   color: var(--in-content-text-color);
@@ -81,6 +85,10 @@ body.config-warning {
   background-size: 16px 16px;
 }
 
+#prefs > tr.locked:dir(rtl) {
+  background-position-x: right 9px;
+}
+
 #prefs > tr > td,
 #prefs > tr > th {
   padding: 4px;