* [doc] comment pr template content

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,5 +1,4 @@
-(Please ***REMOVE*** the following description before submiting)
-
+<!--
 It's ***RECOMMENDED*** to submit typo fix, new demo and tiny bugfix to `dev` branch. New feature and other modifications can be submitted to "domain" branch including `ios`, `android`, `jsfm`, `html5`.
     
 See [Branch Strategy](https://github.com/alibaba/weex/blob/dev/CONTRIBUTING.md#branch-management) for more detail.
@@ -11,3 +10,4 @@ See [Branch Strategy](https://github.com/alibaba/weex/blob/dev/CONTRIBUTING.md#b
 错别字修改、新 demo、较小的 bugfix 都可以直接提到 `dev` 分支；新需求以及任何你不确定影响面的改动，请提交到对应“领域”的分支（`ios`、`android`、`jsfm`、`html5`）。
 
 查看完整的[分支策略 (英文)](https://github.com/alibaba/weex/blob/dev/CONTRIBUTING.md#branch-management)。
+-->