fix(docs): clarify jwtRole is JSON path components (#1129)

src/interfaces.ts

@@ -212,9 +212,10 @@ export interface PostGraphileOptions<
   // null.
   /* @middlewareOnly */
   jwtVerifyOptions?: jwt.VerifyOptions;
-  // A comma separated list of strings that give a path in the jwt from which
-  // to extract the postgres role. If none is provided it will use the key
-  // `role` on the root of the jwt.
+  // An array of (strings) path components that make up the path in the jwt from which to extract the postgres role.
+  // By default, the role is extracted from `token.role`, so the default value is `['role']`.
+  // e.g. `{ iat: 123456789, creds: { local: { role: "my_role" } } }`
+  // the path would be `token.creds.local.role` i.e. `['creds', 'local', 'role']`
   /* @middlewareOnly */
   jwtRole?: Array<string>;
   // The Postgres type identifier for the compound type which will be signed as