docs: Remove PositionType from the docs (#3198)

`PositionType` was deprecated a long time ago, this PR just remove the
non-exported enum and its docs.

doc/flame/components.md

@@ -360,37 +360,6 @@ void onDragUpdate(DragUpdateInfo info) {
 ```
 
 
-### PositionType
-
-```{note}
-If you are using the `CameraComponent` you should not use `PositionType`, but
-instead adding your components directly to the viewport for example if you
-want to use them as a HUD.
-```
-
-If you want to create a HUD (Head-up display) or another component that isn't positioned in relation
-to the game coordinates, you can change the `PositionType` of the component.
-The default `PositionType` is `positionType = PositionType.game` and that can be changed to
-either `PositionType.viewport` or `PositionType.widget` depending on how you want to position
-the component.
-
-- `PositionType.game` (Default) - Respects camera and viewport.
-- `PositionType.viewport` - Respects viewport only (ignores camera).
-- `PositionType.widget` - Position in relation to the coordinate system of the Flutter game
-   widget (i.e. the raw canvas).
-
-Most of your components will probably be positioned according to `PositionType.game`, since you
-want them to respect the `Camera` and the `Viewport`. But quite often you want for example buttons
-and text to always show on the screen, no matter if you move the camera, then you want to use
-`PositionType.viewport`. In some rare cases you want to use `PositionType.widget` to position
-your widgets, when you don't want the component to respect the camera nor the viewport; this could
-for example be for controls or joysticks that would not be ergonomic to use if they had to stay
-within the viewport.
-
-Do note that this setting is only respected if the component is added directly to the root
-`FlameGame` and not as a child component of another component.
-
-
 ### Visibility of components
 
 The recommended way to hide or show a component is usually to add or remove it from the tree

packages/flame/lib/components.dart

@@ -11,7 +11,6 @@ export 'src/components/components_notifier.dart';
 export 'src/components/core/component.dart';
 export 'src/components/core/component_key.dart';
 export 'src/components/core/component_set.dart';
-export 'src/components/core/position_type.dart';
 export 'src/components/custom_painter_component.dart';
 export 'src/components/fps_component.dart';
 export 'src/components/fps_text_component.dart';