clarify keyword arg method error message (JuliaLang#53460)

This is a nice explanatory message, so I think we should make the
wording less obscure.

base/errorshow.jl

@@ -330,7 +330,7 @@ function showerror(io::IO, ex::MethodError)
  if ex.world == typemax(UInt) || isempty(kwargs)
  print(io, "\nThis error has been manually thrown, explicitly, so the method may exist but be intentionally marked as unimplemented.")
  else
- print(io, "\nThis method may not support any kwargs.")
+ print(io, "\nThis method may not support any keyword arguments.")
  end
  elseif hasmethod(f, arg_types) && !hasmethod(f, arg_types, world=ex.world)
  curworld = get_world_counter()

test/errorshow.jl

@@ -669,7 +669,7 @@ end
 
  str = sprint(Base.showerror, MethodError(Core.kwcall, ((; a=3.0), +, 1.0, 2.0), Base.get_world_counter()))
  @test startswith(str, "MethodError: no method matching +(::Float64, ::Float64; a::Float64)")
- @test occursin("This method may not support any kwargs", str)
+ @test occursin("This method may not support any keyword arguments", str)
 
  @test_throws "MethodError: no method matching kwcall()" Core.kwcall()
 end