Move the file manager's sub-menu arrow to the left in RTL

Also reverse the arrow's direction: use \25c0 (left arrow). While here,
move the related ltr/rtl CSS rules together.

Bug: 980503
Change-Id: I08e487a8699dd6f465f106511b4b40f789fc2951
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1935571
Commit-Queue: Austin Tankiang <austinct@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719005}

ui/file_manager/file_manager/foreground/css/menu.css

@@ -37,6 +37,10 @@ cr-menu > [shortcutText]::after {
   padding-inline-start: 30px;
 }
 
+html[dir='rtl'] cr-menu > [shortcutText]::after {
+  float: left;
+}
+
 cr-menu > [sub-menu]::after {
   color: rgb(100, 100, 100);
   content: '\25b6';
@@ -44,12 +48,13 @@ cr-menu > [sub-menu]::after {
   font-size: 0.7em;
 }
 
-cr-menu > [sub-menu][disabled]::after {
-  color: rgba(51, 51, 51, 0.20);
+html[dir='rtl'] cr-menu > [sub-menu]::after {
+  content: '\25c0';
+  float: left;
 }
 
-html[dir='rtl'] cr-menu > [shortcutText]::after {
-  float: left;
+cr-menu > [sub-menu][disabled]::after {
+  color: rgba(51, 51, 51, 0.20);
 }
 
 /* Keeps menu visibile while animating. Fade out animation is performed by