Update aws-resource-cloudfront-function.md

[mgorski-mg]

Issue #, if available: No issue.

Description of changes: Updated AWS::CloudFront::Function documentation.

• Added Examples section
• Added See also section
• Updated FunctionCode property description

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[mgorski-mg]

@joshbean can you merge it?

[joshbean]

Closing this issue or pull request in advance of archiving this repo. For more information about the decision to archive this repo (and others in the 'awsdocs' org), see the announcement on the AWS News Blog.