Zero-detection conditionals should give restart options

[Izaakwltn]

For example, the function, invert-r errors on division by zero, but the problematic number can't be guaranteed to be $0$ outright, as it may turn out to have nonzero bits after an undetermined outer threshold.

This sort of error should give a restart option to raise the precision threshold.

Also Raw-approx-cr may return $0$ when the number is actually negative, but outside of the precision threshold.

Other functions that should be considered with this issue:

• divide-r
• SQRT-R
• LOG-R
• ATAN-R