Class ContainsMatcher

tests/catch.hpp:3136–3139

            bool match( std::string const& source ) const override;
        };
        struct ContainsMatcher : StringMatcherBase {
            ContainsMatcher( CasedString const& comparator );
            bool match( std::string const& source ) const override;
        };
        struct StartsWithMatcher : StringMatcherBase {
            StartsWithMatcher( CasedString const& comparator );
            bool match( std::string const& source ) const override;