RTL: fix margins: public-layout.header.nav-button (#8823)

* RTL: fix margins: public-layout.header.nav-button

* add empty line to meet style guides

app/javascript/styles/mastodon/rtl.scss

@@ -294,4 +294,13 @@ body.rtl {
       }
     }
   }
+
+  .public-layout {
+    .header {
+      .nav-button {
+        margin-left: 8px;
+        margin-right: 0;
+      }
+    }
+  }
 }