update Transfer icons

src/styles/components/transfer.less

@@ -115,7 +115,7 @@
     }
     &-operation {
         display: inline-block;
-        overflow: hidden;
+        //overflow: hidden;
         margin: 0 16px;
         vertical-align: middle;
 
@@ -127,6 +127,13 @@
                 margin-bottom: 12px;
             }
         }
+        .@{btn-prefix-cls}{
+            span {
+                i, span{
+                    vertical-align: middle;
+                }
+            }
+        }
     }
 }
 .select-item(@transfer-prefix-cls, @transfer-item-prefix-cls);