Relative links in markdown (README.md) do not respect the current branch.

To reproduce.

1. Create two branches, say 'master' and 'develop'.
2. Add a file to develop, say 'foo.c'.
3. Edit README.md with a relative link to foo.c:
```
[foo.c](foo.c)
```
4. Push to Stash.

When navigating the link on the develop branch, it points to the master branch which does not have this file. The link does not preserve the URL query parameters, so loses the "?at=develop" branch bit.