refactor(examples): remove prefix not required

[ghost]

https://www.w3.org/2011/rdfa-context/rdfa-1.1

This list of predefined prefixes have been defined for RDFa as an “initial context”: essentially, RDFa users can use these prefixes without having the obligation of defining the prefixes in the HTML code. The same list of prefixes have also been defined for JSON-LD as a JSON-LD Context at the URI http://www.w3.org/2013/json-ld-context/rdfa11; JSON-LD users can use the @context key with that URI as a shorthand to use the same prefixes.

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[ghost]

Don't do CLAs. I'll just leave this here.

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