Optionaly add compatibility operators

Author: AThousandShips

include/godot_cpp/templates/list.hpp

@@ -523,6 +523,11 @@ class List {
 }
 }
 
+// Index operator, kept for compatibility.
+_FORCE_INLINE_ T &operator[](int p_index) {
+return get(p_index);
+}
+
 // Random access to elements, use with care,
 // do not use for iteration.
 T &get(int p_index) {
@@ -538,6 +543,11 @@ class List {
 return I->get();
 }
 
+// Index operator, kept for compatibility.
+_FORCE_INLINE_ const T &operator[](int p_index) const {
+return get(p_index);
+}
+
 // Random access to elements, use with care,
 // do not use for iteration.
 const T &get(int p_index) const {