bind failure with register_vector / "implicit instantiation of undefined template"

Previously (emscripten-1.38.29), this code snippet worked and compiled without error:

```
std::vector VectorAPI::createStringVector()
{
return std::vector();
}

EMSCRIPTEN_BINDINGS(VectorAPI)
{
class_("VectorAPI")
.class_function("createStringVector", &VectorAPI::createStringVector);
register_vector("vector");
}
```

However, on the latest version, I get this instead:

```
In file included from src/api/VectorAPI.cpp:3:
In file included from src/api/VectorAPI.h:6:
/mnt/c/git/emsdk/upstream/emscripten/system/include/emscripten/bind.h:1423:13: error: implicit instantiation of undefined template 'emscripten::internal::RegisterClassMethod, std::__2::allocator > >::*)() const noexcept>'
invoker::template invoke(methodName, callable);
^
/mnt/c/git/emsdk/upstream/emscripten/system/include/emscripten/bind.h:1600:14: note: in instantiation of function template specialization 'emscripten::class_, std::__2::allocator > >, emscripten::internal::NoBaseClass>::function, std::__2::allocator > >::*)() const noexcept>' requested here
.function("size", &VecType::size)
^
src/api/VectorAPI.cpp:26:5: note: in instantiation of function template specialization 'emscripten::register_vector >' requested here
register_vector("vector");
^
/mnt/c/git/emsdk/upstream/emscripten/system/include/emscripten/bind.h:1150:16: note: template is declared here
struct RegisterClassMethod;
^
1 error generated.
shared:ERROR: compiler frontend failed to generate LLVM bitcode, halting
```

I have verified that I'm receiving the same error no matter what vector type I attempt to register (including primitives). I unfortunately can't stay on the older Emscripten version, due to some other issues.