Improve goto_file

[typetetris]

• Try to resolve relative paths relative to the documents parent path (its directory) in case there is a path for the document.

In case there is only one selection of a single character:

• Use textobject_word(.., Inside, ..) to determine the path.

  This way you can stand on the first or last character of the path and it will still use this path (and not the previous one, in case you stood on the first character of the path).

• If the path points to a directory, open the file picker for this directory. General improvements also apply, so if the selected path is relative, it will also be resolved relative to the documents directory if possible.

This might be considered a reason to close #1701

[sheyll]

I really miss the gf behviour I am used from vim a lot I would be really happy if that patch got integrated somehow...

[typetetris]

No time to work on this

[sheyll]

So sad this is being closed... Is there any workaround that comes even remotely close to the elegance of gf?