svg:svg does not work

Hi all,

I found that svg:svg does not work on my end, by 'not work', I mean this tag produce a blank screen on my browsers (chrome and safari). I discovered that if I change svg:svg to svg only, lots of svg come back. Do you guys know what's happened? I don't think I need to change the code like that.

Thank you very much for your help!

首先，使用当前的 LabelMeAnnotationTool 代码在 Chrome 或 Safari 中重现空白屏幕，然后定位受影响的 SVG 标记是在哪里生成或加载的。比较 `svg:svg` 与 `svg` 的行为，并找出相关的浏览器错误或解析差异。当受影响的 SVG 内容无需用户手动编辑标签即可渲染时，即表示完成。

由索引模型根据 Issue 内容生成。