[Serverless] Update role name description

[slobodanadamovic]

I've update the role name parameter description to point out the restrictions we have. But since the specification is generated from SecurityPutRoleRequest.ts (and is shared), it makes this proposed change true for Serverless, but completely wrong for stateful.

Also this change is fragile, anytime someone runs make contrib it will override the specs for stateful as well.

It's not nice, but I could potentially word it in a way to mention that this restriction only applies in Serverless. LMKWYT?

Ideally, we should have this documented in the dedicated docs for Serverles.

[n1v0lg]

LGTM -- just in case, can you run it my @pquentin before merging? (Only when we're ready to merge ofc)

[pquentin]

Thanks! We don't have the option to have serverless-specific descriptions. Any reason not to add "On Elasticsearch Serverless, the role name must ..."?

[slobodanadamovic]

Any reason not to add "On Elasticsearch Serverless, the role name must ..."?

I wasn't sure if there is a better way to document this and avoid mentioning Serverless. But I'm fine with this proposal.