Unexpected panics when onig returns an error when searching

[jszwedko]

Hi all!

We use this crate by way of the grok crate. It appears that search_with_encoding panics if Oniguruma returns an error:

https://github.com/rust-onig/rust-onig/blob/main/onig/src/lib.rs#L632-L650

It seems preferable to me to have the error returned so that it can be handled. Is there a design reason it panics instead? It seems like errors there are not uncommon as we have users of Vector reporting these panics (see: vectordotdev/vector#15199).

Thanks!