[shared_preferences] fix documentation wording (flutter#4986)

The wording of the `SharedPreferences.containsKey` docs was off. This PR improves the documentation.

none. I can open an issue if really necessary.

n.a.

Author: Leptopoda

packages/shared_preferences/shared_preferences/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.2.2
+
+* Updates documentation for `containsKey`.
+
 ## 2.2.1
 
 * Adds pub topics to package metadata.

packages/shared_preferences/shared_preferences/lib/shared_preferences.dart

@@ -121,7 +121,7 @@ class SharedPreferences {
   /// String.
   String? getString(String key) => _preferenceCache[key] as String?;
 
-  /// Returns true if persistent storage the contains the given [key].
+  /// Returns true if the persistent storage contains the given [key].
   bool containsKey(String key) => _preferenceCache.containsKey(key);
 
   /// Reads a set of string values from persistent storage, throwing an

packages/shared_preferences/shared_preferences/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for reading and writing simple key-value pairs.
   Wraps NSUserDefaults on iOS and SharedPreferences on Android.
 repository: https://github.com/flutter/packages/tree/main/packages/shared_preferences/shared_preferences
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+shared_preferences%22
-version: 2.2.1
+version: 2.2.2
 
 environment:
   sdk: ">=2.19.0 <4.0.0"