Full API should be in online documentation

[cmcaine]

The docstrings for e.g. ftest are not present in the generated
documentation but are quite useful. I think the full API should be in
the generated docs.

[nalimilan]

Sure. Would you add them to the relevant files?

[cmcaine]

There's a bunch of stuff missing. How do you feel about @autodocs? https://juliadocs.github.io/Documenter.jl/stable/man/syntax/#@autodocs-block-1

[andreasnoack]

The doc build currently shows

Warning: 8 docstrings not included in the manual:

    GLM.wrkresp! :: Union{Tuple{T}, Tuple{T, GLM.GlmResp{T}}} where T<:(AbstractVector{T} where T<:AbstractFloat)
    GLM.wrkresp :: Tuple{GLM.GlmResp}
    GLM.linpred :: Union{Tuple{GLM.LinPred}, Tuple{GLM.LinPred, Real}}
    GLM.linpred! :: Union{Tuple{Any, GLM.LinPred}, Tuple{Any, GLM.LinPred, Real}}
    GLM.updateμ!
    GLM.delbeta!
    StatsAPI.predict! :: Tuple{Union{NamedTuple{(:prediction, :lower, :upper), <:Tuple{AbstractVector, AbstractVector, AbstractVector}}, AbstractVector}, GLM.AbstractGLM, AbstractMatrix}
    GLM._safe_int :: Tuple{T} where T<:AbstractFloat

so while these have docstring but are missing in the API section, I think that is okay as these should probably not be considered public API. We could consider converting the docstrings to comments to avoid the warnings.