Correct typos in Merge.kt (#2489)

Co-authored-by: yunjoo-park <yunjoopark@linecorp.com>
diff --git a/kotlinx-coroutines-core/common/src/flow/operators/Merge.kt b/kotlinx-coroutines-core/common/src/flow/operators/Merge.kt
index 340d8e3..fae0a16 100644
--- a/kotlinx-coroutines-core/common/src/flow/operators/Merge.kt
+++ b/kotlinx-coroutines-core/common/src/flow/operators/Merge.kt
@@ -34,7 +34,7 @@
  * Transforms elements emitted by the original flow by applying [transform], that returns another flow,
  * and then concatenating and flattening these flows.
  *
- * This method is is a shortcut for `map(transform).flattenConcat()`. See [flattenConcat].
+ * This method is a shortcut for `map(transform).flattenConcat()`. See [flattenConcat].
  *
  * Note that even though this operator looks very familiar, we discourage its usage in a regular application-specific flows.
  * Most likely, suspending operation in [map] operator will be sufficient and linear transformations are much easier to reason about.