Forbid omitting rows in config item and sect-chr

Forbid omitting rows in config item and sect-chr

Forbid omitting rows for tables with const fields: item and sect-chr.
This is consistent with the rule for truncation.

The server expects certain entries in these two tables, and
malfunctions when they're blank.  Omitting them in the builtin tables
has always left them blank, but deities are not supposed to edit them,
and maintainers are supposed to know what they're doing, so the issue
was deemed unimportant and ignored.  However, I plan to blank out
omitted rows in custom tables as well, and then the issue isn't
unimportant anymore.