🐛 Bug

Discovered while testing #5604
It seem impossible to set some shortcut when the underlying combination is a combining key.

For example on US qwerty mac, Alt+E is the combination to do the combining cute accent ´, .ie to type é, you will do Alt-E,E. for á Alt-E,A (...), there are many combining like this Alt-U, for ¨, Alt-I for ˆ.

To Reproduce

Steps to reproduce the behavior:

1. Open napari, preference, shortcut
2. Try to modify one shortcut with a combining key
3. The shortcut assigned contain the combining char.

This will also be printed in terminal :

/FullPath/napari/utils/action_manager.py:319: UserWarning: Alt-E´ does not seem to be a valid shortcut Key.!

(note the .! as well, but I can't figure out where the ! is from)

Expected behavior

Properly register shortcut key.

Environment

napari: 0.5.0a2.dev170+g9cd27b710
Platform: macOS-13.4-arm64-arm-64bit
System: MacOS 13.4
Python: 3.10.0 | packaged by conda-forge | (default, Nov 20 2021, 02:27:15) [Clang 11.1.0 ]
Qt: 5.15.6
PyQt5: 5.15.7
NumPy: 1.24.1
SciPy: 1.10.0
Dask: 2023.1.0
VisPy: 0.12.2
magicgui: 0.6.1
superqt: unknown
in-n-out: 0.1.6
app-model: 0.1.4
npe2: 0.6.2

OpenGL:

• GL version: 2.1 Metal - 83.1
• MAX_TEXTURE_SIZE: 16384

Screens:

• screen 1: resolution 1512x982, scale 2.0

• Input Method might be unusual but looks like the default US keyboard. It might be U.S. International but is is likely not the only one with combining keys.

Additional context