Fix syntax for br--bottom-l class

Author: aubreynortham

scss/_border-radius.scss

@@ -116,8 +116,8 @@
   .br-100-l {  border-radius: $border-radius-circle; }
   .br-pill-l { border-radius: $border-radius-pill; }
   .br--bottom-l {
-      border-radius-top-left: 0;
-      border-radius-top-right: 0;
+      border-top-left-radius: 0;
+      border-top-right-radius: 0;
   }
   .br--top-l {
       border-bottom-left-radius: 0;