Support new Unicode 16.0 Teletext code points

[ali1234]

This will require some refactoring to the way mosaics are handled as the new code points do not define separate glyphs for solid and separated mosaics.

Related links:

https://www.unicode.org/L2/L2019/19025-terminals-prop.pdf

https://gitlab.gnome.org/GNOME/vte/issues/189

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=944609

[ali1234]

Experimental support is now available by running teletext -u <subcommand> (it must be before the subcommand). Separated glyphs are not yet supported. This will also affect HTML output and a font suitable for use with browsers is not yet available.

[ali1234]

Using unicode to render teletext in terminals is currently not possible due to the lack of support for separated/solid mosaics. On hold until something happens on that front.

[ali1234]

An update to the unicode spec has been proposed to add seperated and solid mosaics at different codepoints. It will be a few years until it is widely available.