allow access to help mode at REPL

[bjarthur]

would be convenient if docstrings could be accessed in the usual way with ? at the infiltrator prompt. not sure how hard this would be to implement though.

[pfitzseb]

This is gonna be slightly annoying to implement. In the meantime I'd recommend @doc:

julia> foo(x) = @infiltrate
foo (generic function with 1 method)

julia> foo(3)
Infiltrating foo(x::Int64) at REPL[2]:1:

infil> @doc sin
  sin(x)

  Compute sine of x, where x is in radians.

  sin(A::AbstractMatrix)

  Compute the matrix sine of a square matrix A.

  If A is symmetric or Hermitian, its eigendecomposition (eigen) is used to compute the sine. Otherwise, the sine is
  determined by calling exp.

  Examples
  ≡≡≡≡≡≡≡≡≡≡

  julia> sin(fill(1.0, (2,2)))
  2×2 Matrix{Float64}:
   0.454649  0.454649
   0.454649  0.454649

[bjarthur]

hah! nice. that suffices. i did not know about @doc. maybe document in the REPL help? it is not mentioned there:

infil> ?
  Code entered is evaluated in the current functions module. Note that you cannot change local
  variables, but can assign to globals in a permanent store module.

  The following commands are special cased:
    - `?`: Print this help text.
    - `@trace`: Print the current stack trace.
    - `@locals`: Print local variables.
    - `@exfiltrate`: Save all local variables into the store.
    - `@toggle`: Toggle infiltrating at this `@infiltrate` spot (clear all with `Infiltrator.clear_disabled!()`).
    - `@continue`: Continue to the next infiltration point or exit (shortcut: Ctrl-D).
    - `@exit`: Stop infiltrating for the remainder of this session and exit (on Julia versions prior to
      1.5 this needs to be manually cleared with `Infiltrator.end_session!()`).

[pfitzseb]

That's because it's not specific to Infiltrator at all (the same works in the normal REPL). But yes, adding a note can't hurt: bc6fbcf