Images with src within repo dont render in Readme

Images which has source within the repo doesnt show up in the readme.

Paths with leading slash display as broken image link. While those without a leading slash has an empty value in src tag.

First one (with leading slash) points to path relative to root directory. So the link is broken.

Second one(when there's no leading slash) is caused because of the !89 (closed) (showdown-xss-filter).

example- https://archive.softwareheritage.org/browse/origin/https://github.com/kalpitk/t//visit/2019-04-10T17:13:30.059776+00:00/directory/

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Migrated from T1642 (view on Phabricator)