zsh is the stable shell version. This is now the 5.0 series, which
is the latest version.
zsh-dev is the development version of the shell. This is not currently
in use; the last release here was the 4.7 series.
zsh-doc is preformatted documentation associated with zsh. The main
shell build already comes with manual pages and a Texinfo source, so
you only need this if you want info, HTML or PDF formats and don't
have the tools.
zsh-doc-dev is preformatted documentation associated with zsh-dev.