Add warning suppression feature to the release note

downloads/swan-lake-release-notes/swan-lake-2201.9.0/RELEASE_NOTE.md

@@ -619,13 +619,13 @@ $= future<int> result = start name();
 
 #### Test Framework
 
-- The test framework now supports the parallel execution of tests as an experimental feature. To activate the parallel test execution, simply use the `--parallel` flag with the `bal test` command.
+- The test framework now supports the parallel execution of tests as an experimental feature. To enable parallel test execution, simply use the `--parallel` flag with the `bal test` command.
 
-    ```ballerina
-    bal test --parallel
+    ```bash
+    $ bal test --parallel
     ```
 
-- APIs for mocking client resources is introduced. With these, a client resource can be stubbed to behave in a certain way, previously limited to test double. 
+- APIs for mocking client resource methods is introduced. With these, a client resource can be stubbed to behave in a certain way. Previously, test doubles had to be used to mock client resource methods. 
 
     ```ballerina
     // Sample HTTP Client call
@@ -829,6 +829,8 @@ To view bug fixes, see the GitHub milestone for Swan Lake Update 9 (2201.9.0) of
     scope = "provided"
     ```
 
+- With Update 9, diagnostics issued by the dependency packages are hidden by default. These diagnostics can be printed to the console by passing the `--show-dependency-diagnostics` build option to the CLI command.
+
 ### Bug fixes
 
 To view bug fixes, see the GitHub milestone for Swan Lake Update 9 (2201.9.0) of the repository below.