Add missing operator modifier

Author: LouisCAD

kotlinx-coroutines-core/common/src/Builders.common.kt

@@ -170,7 +170,7 @@ public suspend fun <T> withContext(
  * This inline function calls [withContext].
  */
 @ExperimentalCoroutinesApi
-public suspend inline fun <T> CoroutineDispatcher.invoke(
+public suspend inline operator fun <T> CoroutineDispatcher.invoke(
     noinline block: suspend CoroutineScope.() -> T
 ): T = withContext(this, block)