Bug#1093946: espeak-ng: de-key-ify ruby-kramdown etc

[Chris Hofstaedtler]

Source: espeak-ng
Version: 1.52.0+dfsg-4

Hi,

espeak-ng build-depends on ruby-kramdown, which transitively
build-depends on ruby-em-socksify. ruby-em-socksify is rc-buggy, but
cannot be autoremoved because of this transitive dependency chain,
and espeak-ng itself being a key package.

Please consider using any of the other compatible markdown
implementations.

Thanks,
Chris