PySide6 removes QRegExp

[meshula]

Problem: PySide6 removes QRegExp

  File "miniforge3/envs/otio-py310/lib/python3.10/site-packages/opentimelineview/details_widget.py", line 87, in highlightBlock
    expression = QtCore.QRegExp("(\\{|\\}|\\[|\\]|\\:|\\,)")
AttributeError: module 'PySide6.QtCore' has no attribute 'QRegExp'

QRegularExpression exists, but the regex syntax and class usage has changed substantially: https://doc.qt.io/qt-5/qregularexpression.html#notes-for-qregexp-users

It makes sense to port to the python standard re library, so that the code works in PySide2 and PySide6 without some sort of shim layer, or version selection code.

https://docs.python.org/3/library/re.html

Help welcome if anyone has time to look at this task.

See umbrella task: #1215