[Feature] support .md for links

[damufo]

For compatibility with local editors.
It would be possible for links to also work if the file name has .md.

For example
If I have two files:
Contactos.md
Fred.md

And when placing the link inside contacts:
if I put

[Fred](/note/Fred) # it works

but if I put

[Fred] (Fred.md) # it doesn't work

It would be to make it work in the second case as well.

This second case would be compatible with use from the desktop.
Very thanks.