Allow use of translate sed command "y/" and "tr/"

[jamesmcm]

Currently there is no support for the y/ translate command i.e. y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/ for translating upper-case text to lower-case.

This should first be patched in the sedregex crate, see this issue.

If that is not possible, this could be implemented separately (i.e. its own function).

[developerfred]

Hi @jamesmcm, would love to work on this issue.

[jamesmcm]

@developerfred excellent, I think it'd be best to implement it directly in the sedregex crate if possible.

And it's probably more efficient to just implement it as its own function (rather than building separate regexes).

[developerfred]

@jamesmcm thanks, I will fork this project on gitlab.