PcreException should mention which regexp is actually invalid

[sstok]

Is your feature request related to a problem? Please describe.
When a regex in the ignoreSourceCodeByRegex is invalid this crashes the application with:

[PHP Warning:  preg_match(): Compilation failed: missing closing parenthesis at offset 58 in [...]/infection/vendor/thecodingmachine/safe/generated/pcre.php on line 590]

In PcreException.php line 19:

  [Safe\Exceptions\PcreException (1)]
  PREG_INTERNAL_ERROR: Internal error

Describe the solution you'd like
This is not very helpful because it doesn't show which regex is invalid. Making debugging rather challenging.

I'm not sure this should be resolved here or in the thecodingmachine/safe package?
Instead when this exception is thrown it should show which regexp is invalid. Even better if it's able to mention which config-line is happens at but that's just dreaming 😁

[sidz]

Implemented in #1412