Make is_uri accept all valid schemas

[sassanh]

A URI scheme can contain "-", "+" and "*" as well as digits and letters.

https://www.rfc-editor.org/rfc/rfc3986#page-17

[sassanh]

@tjdevries Sorry to ping you, it's a very small PR if you have the time to check.

[sassanh]

Some context: it is needed because oil.nvim uses oil+ssh:// schema for files editing over ssh and they don't work properly with telescope.nvim because telescope is using plenary to "clean" filenames and plenary doesn't detect oil+ssh as a URI schema.

[Conni2461]

sorry i overlooked that PR. Thanks :)

I had to manually rebase, because github doesnt let me trigger a CI :(

[sassanh]

Thanks!