Ensure prelude contains each symbol only once

Most symbols appear directly in prelude without modules.
There is 'user_data' nested, as it's used rarely and helps organize its types.

Author: Bromeon

gdnative-derive/src/native_script.rs

@@ -22,9 +22,9 @@ pub(crate) fn impl_empty_nativeclass(derive_input: &DeriveInput) -> TokenStream2
 
     quote! {
         #derived
-        impl ::gdnative::prelude::NativeClass for #name {
+        impl ::gdnative::nativescript::NativeClass for #name {
             type Base = ::gdnative::api::Object;
-            type UserData = ::gdnative::prelude::LocalCellData<Self>;
+            type UserData = ::gdnative::nativescript::user_data::LocalCellData<Self>;
 
             fn class_name() -> &'static str {
                 unimplemented!()

gdnative/src/prelude.rs

@@ -1,8 +1,8 @@
 pub use gdnative_core::core_types::{
-    self, Aabb, Basis, ByteArray, Color, ColorArray, Dictionary, Float32Array, GodotError,
-    GodotString, Int32Array, NodePath, Plane, Quat, Rect2, Rid, StringArray, StringName, Transform,
-    Transform2D, TypedArray, Variant, VariantArray, VariantDispatch, VariantOperator, VariantType,
-    Vector2, Vector2Array, Vector3, Vector3Array,
+    Aabb, Basis, ByteArray, Color, ColorArray, Dictionary, Float32Array, GodotError, GodotString,
+    Int32Array, NodePath, Plane, Quat, Rect2, Rid, StringArray, StringName, Transform, Transform2D,
+    TypedArray, Variant, VariantArray, VariantDispatch, VariantOperator, VariantType, Vector2,
+    Vector2Array, Vector3, Vector3Array,
 };
 
 pub use gdnative_core::core_types::{
@@ -16,15 +16,20 @@ pub use gdnative_core::object::{
 };
 
 pub use gdnative_core::nativescript::{
-    self,
     export::{
         ClassBuilder, ExportInfo, InitHandle, Method, MethodBuilder, PropertyUsage, Signal,
         SignalArgument,
     },
-    user_data::{self, Aether, ArcData, LocalCellData, MutexData, RwLockData},
     Instance, NativeClass, NativeClassMethods, RefInstance,
 };
 
+// Re-export selected user_data types, but keep qualified due to rather generic names
+pub mod user_data {
+    pub use gdnative_core::nativescript::user_data::{
+        Aether, ArcData, LocalCellData, MutexData, RwLockData,
+    };
+}
+
 pub use gdnative_core::{
     godot_dbg, godot_error, godot_gdnative_init, godot_gdnative_terminate, godot_init,
     godot_nativescript_init, godot_print, godot_site, godot_warn,