Grants caveats for Snowflake's database roles and Redshift's groups a…

…nd roles (#6120)

website/docs/reference/resource-configs/grants.md

@@ -249,13 +249,14 @@ models:
 
 <div warehouse="Redshift">
 
-* Granting to / revoking from is only fully supported for Redshift users (not groups or roles).
+* Granting to / revoking from is only fully supported for Redshift users (not [groups](https://docs.aws.amazon.com/redshift/latest/dg/r_Groups.html) or [roles](https://docs.aws.amazon.com/redshift/latest/dg/r_roles-managing.html)).
 
 </div>
 
 <div warehouse="Snowflake">
 
 * dbt accounts for the [`copy_grants` configuration](/reference/resource-configs/snowflake-configs#copying-grants) when calculating which grants need to be added or removed.
+* Granting to / revoking from is only fully supported for Snowflake roles (not [database roles](https://docs.snowflake.com/user-guide/security-access-control-overview#types-of-roles)).
 
 </div>