Can't change Alt+[ or Alt+] shortcut (can't use on German keyboard)

Steps to reproduce:

• open Inkscape
• open shortcut settings
• try to change Alt+[ shortcut (rotate by 1 px)

What happened?

The shortcut is missing. [ (rotate step set in preferences) can be changed, and also Ctrl+[ (rotate 90°). They are defined as verbs.

What should have happened?

I should be able to change the shortcut.

Note: The Alt+] shortcut physically doesn't exist on German MacOS keyboards (#1000 (closed)).

The shortcut is defined here:

• for sets of node selections: https://gitlab.com/inkscape/inkscape/-/blob/master/src/ui/tool/control-point-selection.cpp#L582
• for general selections (select tool): https://gitlab.com/inkscape/inkscape/-/blob/master/src/ui/tools/select-tool.cpp#L1043

Inkscape Version and Operating System:

• Inkscape Version: 1.0 (5b275a35d9, 2020-05-03) snap
• Operating System: Ubuntu
• Operating System version: 20.04