Pdd ignore invalid markers

See #94, release log:

• c638368 by @yegor256: #94 rubocop
• b3406f0 by @yegor256: #94 fixed
• 847d8c4 by @yegor256: #94 reproduced
• d64051e by @yegor256: RubyMine badge changed
• fd8a5dd by @yegor256: EO badge changed

Released by Rultor 1.67.1, see build log