beam_lib: Fix spec for all_chunks/1
beam_lib: Fix spec for all_chunks/1

`beam_lib:all_chunks/1` returns the module contained in the given beam
file/binary rather than the `beam_lib` atom if successful. Also see
`scan_beam/2` which originally returns the module.

erlang/otp,emacsmirror/erlang,emacsmirror/erlang,erlang/otp,emacsmirror/erlang,bjorng/otp,emacsmirror/erlang,bjorng/otp,erlang/otp,bjorng/otp,bjorng/otp,erlang/otp,vinoski/otp,erlang/otp,vinoski/otp,bjorng/otp,erlang/otp,bjorng/otp,erlang/otp,vinoski/otp,bjorng/otp,emacsmirror/erlang,vinoski/otp,emacsmirror/erlang,emacsmirror/erlang,vinoski/otp,erlang/otp,vinoski/otp,bjorng/otp,vinoski/otp,erlang/otp,bjorng/otp,emacsmirror/erlang,bjorng/otp,vinoski/otp,emacsmirror/erlang,vinoski/otp,erlang/otp,emacsmirror/erlang,vinoski/otp