feat: support rest of repetitions

[hedhyw]

// x*?            zero or more x, prefer fewer
// x+?            one or more x, prefer fewer
// x??            zero or one x, prefer zero
// x{n,m}?        n or n+1 or ... or m x, prefer fewer
// x{n,}?         n or more x, prefer fewer

https://pkg.go.dev/regexp/syntax

Add them to the readme. Write unit tests.

[ryzheboka]

Hi @hedhyw, can I work on this issue?

[hedhyw]

Hi @hedhyw, can I work on this issue?

Sure! Thanks!