This change fixes cases when a Wiki page refers to a video stored in the
Wiki repository using relative path. It follows the similar case which
has been already implemented for images.
Test plan:
- Create repository and Wiki page
- Clone the Wiki repository
- Add video to it, say `video.mp4`
- Modify the markdown file to refer to the video using `<video
src="video.mp4">`
- Commit the Wiki page
- Observe that the video is properly displayed
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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
