This PR adds support for fish shell with completions. I had to create a separate init file so that I could write the completions in a declarative manner (adapting it from the python completions file was a bit too cumbersome and unclear to me).
Original: #487
The original was closed to be able to make some modifications to the branch.
PR originally created by @ricardomatias
The original was closed to be able to make some modifications to the branch.