fix Alt+` shortcut on non-US layouts

fix Alt+` shortcut on non-US layouts

Origin: upstream, https://code.qt.io/cgit/qt/qtbase.git/commit?id=62e697fd568f6acd
Last-Update: 2022-12-03

Make it possible for non-letter-keys with Latin 1 symbols (`, !, @ etc.)
to participate in shortcuts also, when the keys generate national
symbols on non-Latin layout.

For example, in Russian layout, "`" key generates cyrillic "ё" letter of
national alphabet, so shortcuts with the key should still work
regardless of the actual layout.

Gbp-Pq: Name fix_alt_backtick.diff