[Feature Request]: Keyboard shortcuts reference/help

[mm12]

Checklist

• I am using an up-to-date version.
• I have read the documentation.
• I have searched existing issues.

Description

Listing what key combinations do what is currently unclear. It is not in the documentation or the application, so requires digging in the code.

Solution

Under the help menu, a "keyboard shortcuts" option. This should open a list of keyboard shortcuts and what context you use them in. The universal keybind for this is ctrl + shift + /(in other words,ctrl + ?`). Ideally, it should list items in a manner like:

# keyboard shortcuts
this is a list of keybindings you can use in the app
## context of shortcuts, such as 'selected items'
description of context, such as 'shortcuts that apply to all selected items'
Name of shortcut | current binding | alt binding | default binding 
Name of shortcut | current binding | alt binding | default binding 
Name of shortcut | current binding | alt binding | default binding 
(note - on hover, this should display details about the function of the shortcut)

Additionally, #590 / #814 can be combined with this to allow shortcuts to be customized directly in the help window, rather than needing to exit to the setting menu.

Alternatives

Update the documentation to contain the same list. While this is also desirable, it requires leaving the application and current internet access.
#590 is highly desirable, however having a help menu to list current shortcuts is "universal design" included in a large number of programs. Users can expect to find such an option under help. If the program allows rebinding, it will either directly allow it in the window, or will link to the relevant settings menu.