RegexManager: Add testcase for reproducing bug with regex "^."
RegexManager: Add testcase for reproducing bug with regex "^."

Related issue: https://github.com/newsboat/newsboat/issues/795

newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat