62819586 inline codespan

Inline code with internal newlines was breaking:
```
`foo 
bar baz`
```
This is because kramdown converts the above to 
```latex
{\tt foo
bar baz}
```
and the PolyTeXnex regex to gsub `{\tt ...}` to `\kode{...}` wasn't set for multiline. The `gsub` solution had always been hella ugly, though, so I took this as an opportunity to crack open kramdown and look for `\tt` (typewriter text). The result is that I was able to open up the relevant class and just redefine it to use `\kode` instead of `\tt`. This bodes well for the future, as it means we're now equipped to override other kramdown defaults as it suits us.