Add more hints to the CLI completions about the types of the files

[marcospb19]

Stuff like:

#[clap(value_hint = ValueHint::FilePath)]

Should be added to all Opts fields that support it.

https://github.com/ouch-org/ouch/blob/b50987840ea7fd66f55206a6116fd7169eac8aed/src/opts.rs#L47-L49

Maybe this was forgotten, or there is some problem with hints to Vec fields, we should test if it's working, or at least check the diff of the completions files.