Varargs with array ignores leading arguments.

[Quelklef]

proc f(v: varargs[string]) =
    echo(v)

f("a", ["b", "c"])

Outputs ["b", "c"].

[Quelklef]

Possibly related to #7914

[LemonBoy]

The problem here is that varargs[string] and array[2, string] are linked by a isConvertible relationship and matchesAux is confused by this: it first creates a nkBracket with "a" in it and then overwrites it with the second argument.

I'll take care of this later if nobody else steps up.