update testing.md (#4141)
update testing.md (#4141)

* update testing.md

doc update for jest test configuration.

* Update testing.md

* Update testing.md

* Update docs/_articles/en/lwc/testing.md

Co-authored-by: Emily Kapner <18d4b9a367273be9206967df6cf59310c42e4875@salesforce.com>

Co-authored-by: Emily Kapner <18d4b9a367273be9206967df6cf59310c42e4875@salesforce.com>
forcedotcom/salesforcedx-vscode,forcedotcom/salesforcedx-vscode,forcedotcom/salesforcedx-vscode,forcedotcom/salesforcedx-vscode