Node sockets could already be declared using:
```cpp
add_input<decl::<SOCKET TYPE>>("NAME")
```
They can now additionally be declared with:
```cpp
add_input(socket_type, "NAME")
```
This commit adds the later form to the message extraction regex. Since
they are mutually exclusive, they are now in a non-capturing group
with an | operator.
Reported by Ye Gui in #43295.
4e034b5ecb