Problem: minor problems with the teapot()
Solution: remove the null check, update documentation
Update the builtin-function-list entry. (It implicitly returns 0, but such
functions usually use "none")
Also, tv_get_string_strict() can not return NULL, so remove that check
closes: #12647
Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Sean Dewar <seandewar@users.noreply.github.com>