PKI Role Case Sensitity Declaration for Config Parameters

[danielhass]

Is your feature request related to a problem? Please describe.
We were unsure about the case-sensitivity of several domain related parameters for PKI roles in Vault.

These are documented here: https://developer.hashicorp.com/vault/api-docs/secret/pki#create-update-role

E.g. in case of the parameter allowed_domains we were not sure if the values entered are normalized in some way (as they are DNS names) or if they are case-sensitive during evaluation within Vault. We found that they are indeed case-sensitive. This is not explicitly stated in the docs.

However some parameters state explicitly that they are not case-sensitive, e.g.: https://developer.hashicorp.com/vault/api-docs/secret/pki#key_usage-1 - but in the whole docs page there is not statement given that per default values are case-sensitive and the exception is marked accordingly.

Describe the solution you'd like
I would like to see either a general statement that config parameters are case-sensitive and exceptions are marked accordingly. Or the case-sensitivity of the option should be stated explicitly (however this would hurt readability probably).

Additional context
If I'm missing some statement in docs docs clarifying please point that out. Otherwise I'm also willing to provide a PR for whatever variant the Vault teams sees a better fit.