Remove unnecessary escapes from regexes

Inside `[…]` most chars are literal, such as `*` and `+`, there's no need to escape them.

The hyphen, the colon and the exclamation point are not metacharacters on their own, you can safely use them unescaped.

- `-` is special only when inside `[…]`, between two chars.
- `:` and `!` are only special as the syntax for extended groups `(?…)`.