sh.1: Restore missing builtin commands

PR:		292221
Fixes:		2980318b27 (sh.1: extend the section about getopts)
MFC after:	3 days

bin/sh/sh.1

@@ -2373,7 +2373,7 @@ is not specified by
 .Va optstring
 or if it is missing a required argument,
 the option is considered invalid and:
-.Bl -offset indent
+.Bl -enum
 .It
 If the first character of
 .Va optstring