📖 Fix experiment-related sample code in documentation (#21031)
📖 Fix experiment-related sample code in documentation (#21031)

* Replace user.warn() with userAssert in accordance with gulp test checks

* Replace userAssert() with correct usage of user().warn() to make update more similar to the original spirit of the example

* Move comment to new line

* manual lint

* Replace user().warn() with userAssert

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