Fix typo in text_input.dart (#83247)

packages/flutter/lib/src/services/text_input.dart

@@ -224,7 +224,7 @@ class TextInputType {
 ///
 /// Despite the logical meaning of each action, choosing a particular
 /// [TextInputAction] does not necessarily cause any specific behavior to
-/// happen, other than changing the focus when approapriate. It is up to the
+/// happen, other than changing the focus when appropriate. It is up to the
 /// developer to ensure that the behavior that occurs when an action button is
 /// pressed is appropriate for the action button chosen.
 ///