Add sections to StatusCode documentation

Author: Pi-Cla

src/status.rs

@@ -453,9 +453,9 @@ status_codes! {
     /// 421 Misdirected Request
     /// [RFC7540, Section 9.1.2](https://tools.ietf.org/html/rfc7540#section-9.1.2)
     (421, MISDIRECTED_REQUEST, "Misdirected Request");
-    /// 422 Unprocessable Entity
-    /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
-    (422, UNPROCESSABLE_ENTITY, "Unprocessable Entity");
+    /// 422 Unprocessable Content
+    /// [[RFC9110, Section 15.5.21](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.21)]
+    (422, UNPROCESSABLE_CONTENT, "Unprocessable Content")
     /// 423 Locked
     /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
     (423, LOCKED, "Locked");