Consider validating regexp

[ioggstream]

Note

Consider adding a rule to check for common redos patterns in regexp.
The analysis shouldn't probably go that far, but some patterns (eg *)* are easy to find).
In any case, it's important not to give false confidence to the reader.

cc: @berez23 @emilioSp this issue can be applied to other projects too (eg. on the reuse catalogue).