Make mj_loadModelBuffer a public API.

PiperOrigin-RevId: 843105390
Change-Id: I4058471b4cf64995dd5ab43e9c8c24e322004b62

src/engine/engine_io.h

@@ -69,8 +69,8 @@ MJAPI void mjv_copyModel(mjModel* dest, const mjModel* src);
 // save model to binary file
 MJAPI void mj_saveModel(const mjModel* m, const char* filename, void* buffer, int buffer_sz);
 
-// load binary MJB
-mjModel* mj_loadModelBuffer(const void* buffer, int buffer_sz);
+// load model from binary buffer
+MJAPI mjModel* mj_loadModelBuffer(const void* buffer, int buffer_sz);
 
 // deallocate model
 MJAPI void mj_deleteModel(mjModel* m);