Add 'PyTestReferenceAsStringProvider' for fixtures from pytest.mark.usefixtures attributes.
Add new field 'myTextRange' to 'BaseReference' class.
It's needed for specify the text range for proper highlighting.
For example, to highlight text in a string without quotes.
GitOrigin-RevId: 5b9094169b71dd57d9091d6907346ca69f631ef3