Update about-workflows-long.md (missing 'of') (#35250)

Co-authored-by: Alex Nguyen <[email protected]>

data/reusables/actions/about-workflows-long.md

@@ -1,6 +1,6 @@
 A **workflow** is a configurable automated process that will run one or more jobs. Workflows are defined by a YAML file checked in to your repository and will run when triggered by an event in your repository, or they can be triggered manually, or at a defined schedule.
 
-Workflows are defined in the `.github/workflows` directory in a repository. A repository can have multiple workflows, each which can perform a different set of tasks such as:
+Workflows are defined in the `.github/workflows` directory in a repository. A repository can have multiple workflows, each of which can perform a different set of tasks such as:
 * Building and testing pull requests.
 * Deploying your application every time a release is created.
 * Adding a label whenever a new issue is opened.