We deprecated and removed the camel-case versions of the nGram and edgeNGram filters
a while ago (deprecation in 6, removal ongoing see #50376). I think we
should do the same with the nGram and edgeNGram tokenizers, deprecating the use of these naming variants
in favour of ngram and edge_ngram in 7, preventing newly created indices to use them starting with 8 and removal
in a future version where there can be no indices using them any longer.