Incorrect scope for utf8 characters in labels

[Enivex]

A clear and concise description of what the bug is.

ö does not get the "constant.other.reference.label.latex" that the other letters get

A minimal example to reproduce the issue

• VS Code Version: 1.75.1
• OS Version: W11
• LaTeX-Workshop version if you use it: 9.7.0

[jlelong]

This was because the regex class \w does not contains characters with accent. We know the \p{Alphabetic} utf-8 class.