fix: input 输入框添加clearable属性并输入内容，hover时宽度进行变化

Author: liuzhe

style/web/components/input/_index.less

@@ -78,16 +78,9 @@
   }
 
   &.@{prefix}-input--suffix > span.@{prefix}-input__clear {
-    opacity: 0;
-    visibility: hidden;
     transition: @input-inner-transition;
   }
 
-  &.@{prefix}-input--suffix:hover > span.@{prefix}-input__clear {
-    opacity: 1;
-    visibility: visible;
-  }
-
   // 输入框状态
   .input-status(success);
   .input-status(warning);
@@ -103,6 +96,11 @@
     cursor: pointer;
   }
 
+  .@{prefix}-input__suffix-clear-hidden {
+    opacity: 0;
+    visibility: hidden;
+  }
+
   // 输入框大小
   &.@{prefix}-size-l {
     height: @input-height-l;