Add support for [[file]] and [[file#title]]

[Jackiexiao]

[Git Flow](../adir/git_flow.md)
-> 
[Git Flow](git_flow.md)
->
[[Git Flow]]

Roamresearch / obsidian /foam use a more simple way to link file like [[Git Flow]]

A little more complex [[Git Flow#heading or title]]
[[Git Flow| Git Alias]] show git alias then git flow`

[Jackiexiao]

https://github.com/Jackiexiao/mkdocs-roamlinks-plugin

I fork this project and make some modify