Operating system

This came up during the discussion on #13640, which specifically only adds single character/code point/code unit display for three common text encodings. A nice feature would be to decode and display the entire user selection as a string. Right now, the length of the user selection is not considered for value inspector data, just the starting position is used to read the next 8-bit number, 16-bit

• The set_mode_X() HIL functions need to support returning an error if hardware does not support that mode or if the implementation cannot put the hardware in to that mode at that time. See for an example where panic is used instead of returning an error https://github.com/tock/tock/pull/2629/files.

The Win32 back end includes support for bundle-private fonts as documented here. This should be ported to the X11 back end as well.

See https://github.com/mszoek/airyx/blob/62919a7f4d5e703bf2e09125796dee8fc4241c58/Frameworks/AppKit/Win32.subproj/Win32Display.m#L100-L142