Add note re. discard IP

[gilgongo]

Summary

Adds a note to avoid the misconception that 192.0.2.1 is illustrative for the documentation (as is the usual convention) and not intended to be replaced by the actual IP of the origin server.

Documentation checklist

• [x] The documentation style guide has been adhered to.

[Bydand-dev]

Discord re 192.0.2.1

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