update document for watchPathIgnorePatterns (#4343)

* update document for watchPathIgnorePatterns

* Update Configuration.md

docs/en/Configuration.md

@@ -631,3 +631,10 @@ It is possible to override this setting in individual tests by explicitly callin
 Default: `false`
 
 Indicates whether each individual test should be reported during the run. All errors will also still be shown on the bottom after execution.
+
+### `watchPathIgnorePatterns` [array<string>]
+Default: `[]`
+
+An array of RegExp patterns that are matched against all source file paths before re-running tests in watch mode. If the file path matches any of the patterns, when it is updated, it will not trigger a re-run of tests.
+
+These patterns match against the full path. Use the `<rootDir>` string token to include the path to your project's root directory to prevent it from accidentally ignoring all of your files in different environments that may have different root directories. Example: `["<rootDir>/node_modules/"]`.