Method indent

tests/catch.hpp:6445–6448

		}

		auto indent() const -> size_t {
			auto initial = m_pos == 0 && m_stringIndex == 0 ? m_column.m_initialIndent : std::string::npos;
			return initial == std::string::npos ? m_column.m_indent : initial;
		}

		auto addIndentAndSuffix(std::string const &plain) const -> std::string {
			return std::string(indent(), ' ') + (m_suffix ? plain + "-" : plain);