fix input icon loading (#872)

examples/docs/zh-cn/input.md

@@ -244,7 +244,7 @@
 ```html
 <el-input
   type="textarea"
-  autosize
+  :autosize="{ minRows: 2, maxRows: 4}"
   placeholder="请输入内容"
   v-model="textarea">
 </el-input>

packages/theme-default/src/input.css

@@ -74,10 +74,6 @@
         }
       }
     }
-
-    .el-icon-loading {
-      animation: validating-rotating 1s linear infinite;
-    }
     @m large {
       font-size: var(--input-large-font-size);
 
@@ -209,12 +205,3 @@
     }
   }
 }
-
-@keyframes validating-rotating {
-  0% {
-    transform: translate(0, -50%) rotateZ(0deg);
-  }
-  100% {
-    transform: translate(0, -50%) rotateZ(360deg);
-  }
-}