Don't abort when you find 1 product instead of 2
Don't abort when you find 1 product instead of 2

This occurs when you match a reaction that would break a bond, and it expects
to form two products, but they're somehow joined via another part of the
cyclic species.

For now, we just return 'None' and the reaction is ignored.

It *should* be covered by another type of (unimolecular) reaction family.

nyee/RMG-Py,comocheng/RMG-Py,pierrelb/RMG-Py,enochd/RMG-Py,chatelak/RMG-Py,nickvandewiele/RMG-Py,nickvandewiele/RMG-Py,KEHANG/RMG-Py,KEHANG/RMG-Py,faribas/RMG-Py,faribas/RMG-Py,pierrelb/RMG-Py,nyee/RMG-Py,enochd/RMG-Py,comocheng/RMG-Py,chatelak/RMG-Py