try to recover alias in help>

[Moelf]

Before:

julia> using Base: isvisible as iv

help?> iv
search: div divrem DivideError inv invoke invmod isvalid invperm invpermute! invokelatest InvalidStateException @invoke BitVector @invokelatest code_native

  No documentation found.

  Binding Base.iv does not exist.

this PR:

julia> using Base: isvisible as iv

help?> iv
search: div inv im in if mv

  Base.isvisible is a Function.

  # 1 method for generic function "isvisible" from Base:
   [1] isvisible(sym::Symbol, parent::Module, from::Module)
       @ show.jl:1023

The problem is that it currently tries too hard to recover:

help?> Base.iv
  Base.isvisible is a Function.

  # 1 method for generic function "isvisible" from Base:
   [1] isvisible(sym::Symbol, parent::Module, from::Module)
       @ show.jl:1023

The underlying reason is that by the time REPL doc functions gets the Binding object, it's already in the form of Base.iv -- regardless of help?> iv or help?> Base.iv

cc. @JeffBezanson for pointing to the internal function

[JeffBezanson]

Here's a patch that should work:

--- a/base/docs/bindings.jl
+++ b/base/docs/bindings.jl
@@ -10,7 +10,12 @@ struct Binding
         # Normalise the binding module for module symbols so that:
         #   Binding(Base, :Base) === Binding(Main, :Base)
         m = nameof(m) === v ? parentmodule(m) : m
-        new(Base.binding_module(m, v), v)
+        if ccall(:jl_binding_owner, Ptr{Cvoid}, (Any,Any), m, v) == C_NULL
+            new(Base.binding_module(m, v), v)
+        else
+            b = ccall(:jl_binding_owner, Any, (Any,Any), m, v)::Core.Binding
+            new(b.globalref.mod, b.globalref.name)
+        end
     end
 end

The basic problem is that this code assumed "resolving" a symbol can only change the module and not the name, so this fixes that. We can probably go ahead with this since it's at least an improvement, but we could try to get fancier and preserve the original name so we can print something useful like iv is a renamed import of isvisible.

[Moelf]

Tests have been added