require-space-after-line-comment: add except option

According to #592 and #593 we've decided to make except option to this rule to pass there a list of allowed characters

>  Do we have another rule with value: true?

Except for `maximumLineLength` nope, but we're toying with that idea couple of times.

> Just if we defining this rule with an object it's means value: true by self. Isn't it?

It is! This is why i wrote "although it makes sense", i thinking mostly about coherence with other rule values