== Why is this an issue?
The use of punctuation characters to separate subgroups in a number can make the number more readable. For instance consider 1,000,000,000 versus 1000000000. But when the grouping is irregular, such as 1,000,00,000; it indicates an error.
This rule raises an issue when underscores (``++_++``) are used to break a number into irregular subgroups.
