Remove calls to deprecated exists_key
Remove calls to deprecated exists_key

EXISTS-KEY is the way to go now

zostay/perl6-pod-to-markdown,zostay/perl6-pod-to-markdown,softmoth/perl6-pod-to-markdown,softmoth/perl6-pod-to-markdown,jpve/perl6-pod-to-markdown,jpve/perl6-pod-to-markdown