Fix outdated references to singleton functions
@@ -441,10 +441,10 @@ A singleton is a single instance of a component that can be retrieved without an
```c
// Set singleton component
-ecs_set_singleton(world, Position, {10, 20});
+ecs_singleton_set(world, Position, {10, 20});
// Get singleton component
-const Position *p = ecs_get_singleton(world, Position);
+const Position *p = ecs_singleton_get(world, Position);
```
```cpp
// Set singleton component
