Check for Vararg{T,N} in typemap: sig_match_by_type_simple

[timholy]

Fixes #16623

[timholy]

I would classify this as a "narrow" fix, but it works in the cases I tested. @vtjnash, since you know typemap.c well, it might make some sense to see if you can think of cases that this simple fix wouldn't catch.

[vtjnash]

also likely need the same fix @ https://github.com/JuliaLang/julia/pull/16627/files#diff-213db5d6a6c93b12384ade73dbb25e1aR155, although I don't know of any case where that can be triggered (currently). Might also want to check that very long argument list method matches ending in a limited vararg don't get incorrectly truncated as they get inserted into the cache to look like an unlimited vararg.

[timholy]

Did you mean to link somewhere else? That link is for the diff in this PR.

[vtjnash]

oh, i forgot that github won't let me link to a line number for a PR. the corrected link to sig_match_simple is

julia/src/typemap.c

Line 155 in fab4a62

if (va) {