Adapt threadListAvatars to RTL langs

Fixed: twpowertools:19
Change-Id: I55bcdfb68ca18e0bd0b7fac55710b2e4a866ec89
diff --git a/src/static/css/thread_list_avatars.css b/src/static/css/thread_list_avatars.css
index 9983733..2dcb29b 100644
--- a/src/static/css/thread_list_avatars.css
+++ b/src/static/css/thread_list_avatars.css
@@ -3,7 +3,7 @@
   flex-direction: row;
   min-width: 108px;
   overflow-x: hidden;
-  margin-left: 14px;
+  margin-inline-start: 14px;
 }
 
 .TWPT-avatars .TWPT-avatar {
@@ -12,7 +12,7 @@
   align-self: center;
   border-width: 0;
   border-radius: 50%;
-  margin-left: 6px;
+  margin-inline-start: 6px;
   background-color: white;
   background-position: center;
   background-size: contain;