Qt6's QFont::setWeight() now takes a QFont::Weight enum instead of
a raw int, so uic-generated code from the old <weight>75/50</weight>
XML properties fails to compile (worked on GCC via -fpermissive,
but hard error on Apple Clang for the macOS build).
<bold> is already set on all affected widgets, so <weight> was
redundant and can be dropped without any visual change.