Cargo install doesn't do localisation install for you

[akkuankka]

Because localisation files are not hard-coded into the binary with includestr!() or such, with the binary installed you can call matheriser from any old where which is fine and good but it does mean that the localisation files are going to have to end up somewhere globally accessible & sensible.

It makes sense that these files should go in ~/.local/share/matheriser ( possibly /.cargo/matheriser, more on that later ), but getting them there for the user is somewhat of a deal.

There could be a post_install.sh that copies the language files into whatever directory it ends up being, but this assumes that the end user has a functioning bash (i.e. not Windows users probably). Because of this, and because its an extra step, and because its a random shell script which we expect users to just go with, and because using things that aren't rust don't seem particularly rusty I'd rather have a way of packing up the assets.

There is a an rfc on cargo install that would allow for an install.rs file that specifies where asset files, manpages, etc etc go. It was postponed in March of this year, for reasons that seem to amount to 'it wasn't really being worked-upon' or something like that, I don't really know how the Rust RFC system works, but I could learn if it became a priority to not use a shell script.
If someone else gets that RFC back off the ground we should definitely use that.