`bat --list-languages` already emits each entry in `name:matchers`
form, which is the format `_describe` consumes directly. The previous
awk script split each line on `:` and re-emitted `$1:$2`, which is
byte-identical to the input.
Verified with `diff <(bat --list-languages) <(bat --list-languages |
awk -F: '{ printf("%s:%s\\n", $1, $2) }')` against the current
syntax set.
The previous awk script in `bat.zsh.in` split each line of
`bat --list-languages` on `:` or `,` and emitted every field as a
completion candidate, including the second column. That column lists
file matchers, which can be plain extensions (`rs`), globs (`*.rs`),
absolute paths (`/etc/profile`), or filenames (`Containerfile`). None
of those parse as `-l` arguments, so completing them produces
`unknown syntax` errors.
Switch to splitting on `:` only and emit the language name as the
completion value with the file-matcher list as its description, which
matches the bash completion's behavior.
Closes#3735.
truffle