Hiding undocumented enum values?

There are several GUC enums that accept values that aren't documented
anywhere; the worst offender being backslash_quote, which has more
undocumented spellings than documented ones:

/*
* Although only "on", "off", and "safe_encoding" are documented, we
* accept all the likely variants of "on" and "off".
*/
static const struct config_enum_entry backslash_quote_options[] = {
{"safe_encoding", BACKSLASH_QUOTE_SAFE_ENCODING},
{"on", BACKSLASH_QUOTE_ON},
{"off", BACKSLASH_QUOTE_OFF},
{"true", BACKSLASH_QUOTE_ON},
{"false", BACKSLASH_QUOTE_OFF},
{"yes", BACKSLASH_QUOTE_ON},
{"no", BACKSLASH_QUOTE_OFF},
{"1", BACKSLASH_QUOTE_ON},
{"0", BACKSLASH_QUOTE_OFF},
{NULL, 0}
};

I am wondering if it's a good idea to hide the redundant entries
to reduce clutter in the pg_settings display. (We could do this
by adding a "hidden" boolean to struct config_enum_entry.)
Thoughts?

regards, tom lane