Allow multiple syllables between separators

[mitchchn]

The wordlist generator should be able to produce passwords with multiple "chunks" (words or syllables) between each separator.

[robyoder]

For these and other issues, I think it would be useful to stop referring to the wordlist generator. As you said, word lists and syllable lists have very different uses. We would expect something like this for a syllable list generator, but I don't think we ever need this for a word list generator. I'd like to keep the word list completely separate and basically unchanged from the way it currently functions.

[mitchchn]

@robyoder: then we need another issue to formally separate the two generators. :) Maybe SyllableRecipe can compose WLRecipe with extra options?

[robyoder]

Compose or extend?