Add note for adding multiple cron schedules to a function

[welteki]

Description

Add note for adding multiple cron schedules to a function.

Motivation and Context

• I have raised an issue to propose this change (required)

Document support for multiple cron schedules.

How Has This Been Tested?

Ran the site locally with docker and verified the edited pages render correctly.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have signed-off my commits with git commit -s