Update docs/rules/built-in-rules.md

Author: JLekawa

docs/rules/built-in-rules.md

@@ -132,6 +132,8 @@ Within the Arazzo family of rules, there are rules for the main Arazzo specifica
 
 ### Spot [ deprecated ]
 
+The below rules are being migrated to Spot:
+
 - [no-criteria-xpath](./spot/no-criteria-xpath.md): the `xpath` type criteria is not supported by Spot.
 - [parameters-not-in-body](./spot/parameters-not-in-body.md): the `in` section inside `parameters` must not contain a `body`.
 - [version-enum](./spot/version-enum.md): the `version` property must be one of the supported values.