GDScript: Make array literal typed if for loop variable type is specified

[dalexeev]

• Closes Statically incorrect type annotations are permitted on for loop variables #82021.

Treat an array literal as typed if the for loop variable type is specified:

for x: int in [1, 2, 3]:
#             ^^^^^^^^^
#             Array[int]

This is an implicit behavior that I don't really like, but I think it's consistent with other cases.

[vnen]

This is an implicit behavior that I don't really like, but I think it's consistent with other cases.

Note that this array cannot be accessed or changed by the user, so in practice it makes no difference if it's implicitly typed or not. In the context of the for loop, it makes sense to infer the list to the strictest type possible.

[YuriSizov]

Thanks!