Support multiple commands with same name

[mflint]

We might get a situation where there are duplicate commands with the same name. (eg: fc for Linux/macOS is different from fc for Windows)

The app should handle that.

In particular:

• "dynamic quick actions" (created by the Shortcuts class, and appear when 3D-touching the app icon) be able to identify the correct command, even if two commands have the same name
• this means the Preferences class also needs to identify the correct command when it keeps a list of the latest commands seen
• ... which implies that we need a way of uniquely identifying a command, not by its name

Potential solutions

• maybe change the app so it identifies commands by command-name and platform-name, instead of just command-name

Implications

• "See Also" finds related commands by name, so if there are multiple commands with that name, it might need to show them all
• Spotlight search will show multiple commands with the same name - tapping on a result should open the correct command
• Favourites will need to change too