Vim only use the `~` prefix if the encoding is "latin1". We can just treat it as though the encoding is Unicode, and match the other places we format printable characters. Note that for Vim, if `'display'` contains "uhex", then all unprintable characters are shown in hex, including control characters (`^C`, etc.). IdeaVim does not support the `'display'` option.

Not sure why IdeaVim has used hex. Vim appears to have used decimal for at least 20 years.

List is based on Vim's documentation, although not all digraphs are documented. Additional digraphs are added based on the output of `:digraphs`. These additional digraphs include some digraphs that produce the same character, so the code is updated to handle duplicates, with the same ordering/priority as Vim.

Extra digraphs include the Euro symbol (`=e` and `Eu`), quadruple prime (`4'`) and bullet (`oo`), amongst others.

Also removes a number of non-standard digraphs. The symbols generated don't match the descriptions. The code appears to be private use, so are not reliable. Once custom digraphs are implemented, they can be easily added back in `~/.ideavimrc`