Pattern error types

[Dym03]

Fixes #166
Initial proposal of the restructure of the PatterError, inspired by code proposed in Issue #166.
Added thiserror crate for the ease of work with the error messages, if this would be a problem please let me know.
Had to set version, due to rustc 1.63 used, because latest versions require rustc 1.68.

Also while coding wondered if maybe merging the newly created enum with the PatternError wouldn't be cleaner, but not sure. Showcase below

pub enum PatternError {
    /// Wildcard should be only `*` or `**`
    #[error("Patter error at position {pos}: wildcards are either regular `*` or recursive `**` ")]
    InvalidWildcards {pos: usize},
    ...
}

[tgross35]

Added thiserror crate for the ease of work with the error messages, if this would be a problem please let me know. Had to set version, due to rustc 1.63 used, because latest versions require rustc 1.68.

It's not a problem per se, but I think we may as well avoid the extra dependencies here. All we need is the Display impl, which is only a few extra lines to write by hand.

Also while coding wondered if maybe merging the newly created enum with the PatternError wouldn't be cleaner, but not sure. Showcase below

pub enum PatternError {
    /// Wildcard should be only `*` or `**`
    #[error("Patter error at position {pos}: wildcards are either regular `*` or recursive `**` ")]
    InvalidWildcards {pos: usize},
    ...
}

This crossed my mind as well. Since pos is common to all error kinds, I think the current structure is okay. But I would remove the Eq and Copy traits so we have more flexibility adding fields to the enum in the future.

Could you also make PatternError non_exhaustive?

[tgross35]

I think this looks pretty good with the two small nits here. Unfortunately we can't merge this right away though; this is of course a breaking change, so we need to wait on some decisions about how to handle 1.0 first.

[tgross35]

Missing trailing newline (changes to this file can just be dropped)

[tgross35]

Error strings usually start with a lowercase letter

[Dym03]

Sure thing, thanks for the feedback. I will try to work on some other things that could bring the glob closer to 1.0 :)