qmllint fails when given files names with backslashes on Windows

Calling `pyside6-project qmllint` automatically generates type and `qmldir` files for classes to be registered with QML.

However, it ultimately fails when running on Windows as the paths get passed to `pyside6-qmllint` with Windows-style \ separators, but `importQmlDirs` (see qtdeclarative/src/qmlcompiler/qqmljsimporter.cpp at dev · qt/qtdeclarative (github.com)) requires the file to end in `/qmldir` (with a forward slash).

Manually re-running the command but replacing that final \ with a / causes the command to work without issue, but this prevents using `pyside6-project` as recommended.

EDIT: Fixed typo, `/qmllint` -> `/qmldir`