Bug when documenting callable parametric struct

[jaemolihm]

Similar to #20087, but for parametric structs.

"""Docs for Parametric struct """
struct Parametric{T} end

"""Docs for Parametric func"""
function (f::Parametric{T})(x) where {T} end


"""Docs for NonParametric struct """
struct NonParametric end

"""Docs for NonParametric func"""
function (f::NonParametric)(x) end

@doc Parametric
@doc NonParametric
@doc f

Output:

julia> @doc Parametric
  Docs for Parametric struct
julia> @doc NonParametric
  Docs for NonParametric struct

  Docs for NonParametric func
julia> @doc f
  Docs for Parametric func

julia> versioninfo()
Julia Version 1.7.0
Commit 3bf9d17731 (2021-11-30 12:12 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Xeon(R) CPU E5-2630 v3 @ 2.40GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-12.0.1 (ORCJIT, haswell)
Environment:
  JULIA = /home/jmlim/appl/julia-1.7.0/bin/julia
  JULIA_EDITOR = code
  JULIA_NUM_THREADS = 1

[fingolfin]

I believe this was fixed by @mgkurtz in PR #45529. To wit, in Julia 1.9 we get:

julia> @doc Parametric
  Docs for Parametric struct

  Docs for Parametric func

julia> @doc NonParametric
  Docs for NonParametric struct

  Docs for NonParametric func

julia> @doc f
  No documentation found.

  Binding f does not exist.