sdl3: Update mouse motion to use SDL3's floats

Author: RobLoach

demo/sdl3/nuklear_sdl3_renderer.h

@@ -321,11 +321,11 @@ nk_sdl_handle_event(struct nk_context* ctx, SDL_Event *evt)
             return 1;
 
         case SDL_EVENT_MOUSE_MOTION:
-            if (ctx->input.mouse.grabbed) {
-                int x = (int)ctx->input.mouse.prev.x, y = (int)ctx->input.mouse.prev.y;
-                nk_input_motion(ctx, x + evt->motion.xrel, y + evt->motion.yrel);
-            }
-            else nk_input_motion(ctx, evt->motion.x, evt->motion.y);
+            ctx->input.mouse.prev = ctx->input.mouse.pos;
+            ctx->input.mouse.delta.x = evt->motion.xrel;
+            ctx->input.mouse.delta.y = evt->motion.yrel;
+            ctx->input.mouse.pos.x = evt->motion.x;
+            ctx->input.mouse.pos.y = evt->motion.y;
             return 1;
 
         case SDL_EVENT_TEXT_INPUT: