[ trivial ] driver --> ecosystem for legacy docs

Author: andf-mongodb

source/core/security-client-side-encryption.txt

@@ -88,7 +88,7 @@ for client-side field level encryption, see
 
 For an end-to-end procedure for configuring field level encryption using
 select MongoDB 4.2+ compatible drivers, see the 
-:driver:`Client Side Field Level Encryption Guide
+:ecosystem:`Client Side Field Level Encryption Guide
 </security/client-side-field-level-encryption-guide>`.
 
 Supported Encryption Methods