fix: input 使用 UniInputElement 类型

pages/component/input/input.uvue

@@ -276,11 +276,11 @@
         this.onMaxLengthInputValue = event.detail.value
       },
       setCursor: function (cursor : number) {
-        (this.$refs['input'] as Element).focus();
+        (this.$refs['input'] as UniInputElement).focus();
         this.cursor = cursor;
       },
       setSelection: function (selectionStart : number, selectionEnd : number) {
-        (this.$refs['input2'] as Element).focus();
+        (this.$refs['input2'] as UniInputElement).focus();
         this.selectionStart = selectionStart;
         this.selectionEnd = selectionEnd;
       },