Convert mju_error and mju_warning to variadic functions, supporting printf-like arguments. The functions mju_error_i, mju_error_s, mju_warning_i, and mju_warning_s are now deprecated.

PiperOrigin-RevId: 515431052
Change-Id: I440de0cb417ce216b6d636a5d86dc9ef6cc1fc06

src/user/user_composite.cc

@@ -206,7 +206,7 @@ void mjCComposite::SetDefault(void) {
     break;
   default:
     // SHOULD NOT OCCUR
-    mju_error_i("Invalid composite type: %d", type);
+    mju_error("Invalid composite type: %d", type);
     break;
   }
 }
@@ -543,7 +543,7 @@ bool mjCComposite::MakeCable(mjCModel* model, mjCBody* body, char* error, int er
           break;
         default:
           // SHOULD NOT OCCUR
-          mju_error_i("Invalid composite shape: %d", curve[k]);
+          mju_error("Invalid composite shape: %d", curve[k]);
           break;
         }
       }