l10n: zh_CN: Update Translation of "tag"

- "tag" translated as "标签".
- "annotated tag" translated as "附注标签".
- "mergetag" translated as "合并标签".
- "tag name" translated as "标签名称".
- Relevant adjustments.

Signed-off-by: Ray Chen <oldsharp@gmail.com>
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>