Improve single-line block comment check

[MikailBag]

Previously it was implemented using a regex. However this approach is inherently not accurate, leading to problems like iss. 1079.

This patch converts to it AST-based check pass which should have no false-positives.

[yegor256]

@rultor merge

[rultor]

@rultor merge

@yegor256 OK, I'll try to merge now. You can check the progress of the merge here

[rultor]

@rultor merge

@yegor256 Done! FYI, the full log is here (took me 6min)