Doc: Polish docs for qmlformat

https://doc.qt.io/qt-6/qtquick-tools-and-utilities.html#qmlformat could benefit from some love:

• It implies that elements are sorted/grouped by default. In reality, this doesn't occur unless --normalize/-n is used.
• It explicitly says that imports are sorted. In reality, they're not (QTBUG-107211)
• It doesn't say anything about the .qmlformat.ini settings files (a default one can be obtained by passing --write-defaults)