Basic Docs for SCEP-Level logging. (#927)

Adds docs for recently added configuration flag.

Author: kitography

content/vault/v1.20.x/content/api-docs/secret/pki/issuance.mdx

@@ -883,6 +883,7 @@ $ curl \
     "enabled": true,
     "external_validation": {},
     "last_updated": "2025-05-26T09:59:24-04:00",
+    "log_level" : "WARN",
     "restrict_ca_chain_to_issuer": true
   }
 }
@@ -940,6 +941,8 @@ refer to the [SCEP documentation](/vault/docs/secrets/pki/scep).
   chain within GetCACert responses. Set `restrict_ca_chain_to_issuer` to `true`
   to make your PKI configuration compatible with Microsoft Intune.
 
+- `log_level` `(string: "")` - the log level to use for logging SCEP-specific requests.  One of standard log levels: `TRACE`, `DEBUG`, `INFO`, `WARN`, `ERROR`, or use the empty string to reset to the vault-level default. (1.20.1+ only)
+
 - `external_validation` `(map[string]map[string]string: "")` - a map specifying
   configuration for 3rd party validation of SCEP requests. Map keys can
 	be any of the following: