cleaned up an error in the transition syntax

library/scss/partials/_mixins.scss

@@ -33,13 +33,11 @@ USAGE: @include transition(all 0.2s ease-in-out);
 */
 
 @mixin transition($transition...) {
-	// defining prefixes so we can use them in mixins below
-	$prefixes:      ("-webkit",  "");
+  // defining prefixes so we can use them in mixins below
+  $prefixes:      ("-webkit-", "" );
   @each $prefix in $prefixes {
-    #{$prefix}-transition: $transition;
+    #{$prefix}transition: $transition;
   }
-
-  transition: $transition;
 }
 
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