WIP: making error locations in julia-repl clickable

By: Tamás K. Papp

Re-posted from: https://tpapp.github.io/post/wip-julia-repl-clickable/

I scratched a long-standing itch and made locations in error messages
"clickable" in julia-repl. Not yet merged into master, the change
is in the
clickable-locations
branch.

Testing is needed because of some hacks (again, I am not an Emacs
expert), I will see if there are issues then merge it. This is what it
looks like, those red and orange lines take you to the source:

julia> include("/tmp/Foo.jl")
ERROR: LoadError: UndefVarError: T not defined
Stacktrace:
 [1] include_from_node1(::String) at ./loading.jl:576
 [2] include(::String) at ./sysimg.jl:14
while loading /tmp/Foo.jl, in expression starting on line 9

julia>