[Python] Fix needed for highlighting numbers using underscores

[ghost]

Python added support for using underscores in numbers as visual separators. Using them in that way causes the highlight color of the number to split from one color to another at the underscore. In the default blue scheme, for example, the number 50_000 will have the 50 in purple and the _000 in blue – I've attached an image as an example:

Could this be fixed to ensure that the entire number stays the same color?

[Veratil]

This is part of the grammar detection, not the syntax theme. You should open an issue with atom/language-python.