special show for AbstractVector{Method} for ::MIMEtext/plain

which is currently done for text/html
this enables the jump-to-method thingy from JuliaLang#22007 to be used with methodswith(Foo) also
This also prevents large spacing in the printing, since the general vector output prints with equal spacing for all elements, and some methods have very long signatures

base/methodshow.jl

@@ -289,8 +289,8 @@ end
 
 show(io::IO, mime::MIME"text/html", mt::MethodTable) = show(io, mime, MethodList(mt))
 
-# pretty-printing of Vector{Method} for output of methodswith:
-function show(io::IO, mt::Vector{Method})
+# pretty-printing of AbstractVector{Method} for output of methodswith:
+function show(io::IO, mime::MIME"text/plain", mt::AbstractVector{Method})
     for (i, m) in enumerate(mt)
         print(io, "[$(i)] ")
         show(io, m)