// strictly allowed by RFC 1123. This will result in an error when parsing
// date strings that occur in the first 9 days of a given month.
// In general [RFC1123Z] should be used instead of [RFC1123] for servers
// that insist on that format, and [RFC3339] should be preferred for new protocols.
// [RFC3339], [RFC822], [RFC822Z], [RFC1123], and [RFC1123Z] are useful for formatting;
// when used with time.Parse they do not accept all the time formats

			// Escaped non-word characters are always themselves.
			// PCRE is not quite so rigorous: it accepts things like
			// \q, but we don't. We once rejected \_, but too many
			// programs and people insist on using it, so allow \_.
			return c, t, nil
		}

	// Octal escapes.
	case '1', '2', '3', '4', '5', '6', '7':
		// Single non-zero digit is a backreference; not supported