REPL: Fix incorrect docstring for .. (JuliaLang#40563) (JuliaLang#40607)

This PR fixes JuliaLang#40563 .
This is essentially a mirror of JuliaLang#39975 . Please refer to it for more information.

Author: Pramodh Gopalan V

stdlib/REPL/src/docview.jl

@@ -224,7 +224,7 @@ function lookup_doc(ex)
             op = str[1:end-1]
             eq = isdotted ? ".=" : "="
             return Markdown.parse("`x $op= y` is a synonym for `x $eq x $op y`")
-        elseif isdotted
+        elseif isdotted && ex !== :(..)
             op = str[2:end]
             return Markdown.parse("`x $ex y` is akin to `broadcast($op, x, y)`. See [`broadcast`](@ref).")
         end

stdlib/REPL/test/repl.jl

@@ -1096,6 +1096,9 @@ end
 # Issue 39427
 @test occursin("does not exist", sprint(show, help_result(":=")))
 
+# Issue #40563
+@test occursin("does not exist", sprint(show, help_result("..")))
+
 # Issue #25930
 
 # Brief and extended docs (issue #25930)