Implement typed dictionaries

modules/gdscript/tests/scripts/parser/features/typed_dictionaries.gd

@@ -0,0 +1,5 @@
+func test():
+	var my_dictionary: Dictionary[int, String] = { 1: "one", 2: "two", 3: "three" }
+	var inferred_dictionary := { 1: "one", 2: "two", 3: "three" } # This is Dictionary[int, String].
+	print(my_dictionary)
+	print(inferred_dictionary)

modules/gdscript/tests/scripts/parser/features/typed_dictionaries.out

@@ -0,0 +1,3 @@
+GDTEST_OK
+{ 1: "one", 2: "two", 3: "three" }
+{ 1: "one", 2: "two", 3: "three" }