Function/class names with digits or XID_Continue characters are highlighted incorrectly

# Bug report

### Bug description:

`def 454545():` highlighting 

![Image](https://github.com/user-attachments/assets/02834df0-4a5a-47bd-b0b0-345baccca521)

![Image](https://github.com/user-attachments/assets/939a1bc4-24c7-4d08-94c6-b7ca19e82c9e)

### CPython versions tested on:

3.12, 3.14, 3.13, 3.9, 3.10, 3.11, 3.15

### Operating systems tested on:

Windows