Add prefix position to hx CLI file args

[bheylin]

Resolves #5437

A cursor position can now be specified using common prefix notation used by vim, nvim, kak, emacs and nano.

hx +10 Cargo.toml

This prefix notation also allows the user to set the cursor at the end of the file.

hx +: Cargo.toml

This allows hx to play nicely with other tools that want to open a file at a given position using prefix notation.

The existing postfix notation can still be used (hx Cargo.toml:10) but has been extended to support jumping to the end of a buffer.

hx Cargo.toml:

The prefix notation works for each file in the list.

hx +10 Cargo.toml +20 README

and can be intermixed with postfix notation.

hx +10 Cargo.toml README:20

Prefix notation also supports column indexing.

hx +10:20 Cargo.toml

[the-mikedavis]

Duplicate of #5603

[bheylin]

Duplicate of #5603

I would highlight that this PR implements file positioning just like Kakoune's CLI
so both positioning and the ability to jump to EOF.

[the-mikedavis]

This was partially superseded by #8521

We wanted to support +N syntax only for tools like less that assume that editors support that syntax. Since we have that and the suffix way of specifying line/column (e.g. file.txt:5:3) I think we support enough ways to open lines/cols. I'm not sure what the use-case is for Kakoune's support of opening at the end with :. I think it would be ok to add that syntax (specifically file.txt:, not +:) in a separate PR but I will close this out because we want to keep the position handling relatively small/simple and supporting multiple +Ns is not necessary

[bheylin]

@the-mikedavis All good Mike, as long as it works!

I'm not sure what the use-case is for Kakoune's support of opening at the end with :.

I'm also not sure where that came from, I presumed it was some sort of standard across editors.

Anyways my need here was to integrate helix into zellij with line number support and that's taken care of now.