Keyboard shortcut alt-5 conflicts with { character on macOS with a French keyboard

[Ecco]

TIC-80 is currently unusable for Mac users in France. Indeed, to type a brace character { on a French Mac keyboard you're supposed to hit Alt-(.

However, when a user with a French Mac keyboard layout presses Alt-(, TIC-80 switches to the Music editor instead of yielding a { character.

Note: On those keyboards, the ( key is shared with the 5 key. To get a 5 you're supposed to press Shift-(. I guess this somehow trips TIC-80 that confuses Alt-( with the Alt-5 shortcut (that, on this keyboard, should therefore be Alt-Shift-(.

I tested this on the current macOS release as well as on the latest HTML build of the main branch. The bug is present in both builds.

[aliceisjustplaying]

There is a way to detect they keyboard layout in SDL2: https://gist.github.com/g2p/8597984

[aliceisjustplaying]

@Ecco PR with fix at #2663.