pydoc VS zeal-at-point

I haven't used Dash, so I don't know the specifics of what it works, but if it works like running pydoc or godoc or whatever Java has inside your text editor, here is a plugin for pydoc inside emacs and here's another for godoc (as part of a larger mode for go). I just tested godoc and it seems to work fine, if a little too basic.

And if you do stick with Zeal, there is the zeal-at-point package. You still need the external Zeal reader, but at least it gives you a convenient way to lookup stuff in it from within Emacs.

I’ve used Zeal (a cross-platform Dash alternative) with zeal-at-point. Recently though I’ve gone all in on LSP, and highly recommended. Speaking from experience, at least for Haskell and Go, the integrated documentation is excellent.