Apply suggestions from code review

Co-authored-by: Tom Hvitved <hvitved@github.com>

Author: geoffw0

rust/ql/lib/codeql/rust/Concepts.qll

@@ -179,15 +179,7 @@ module SqlSanitization {
 module Cryptography {
   private import codeql.rust.internal.ConceptsShared::Cryptography as SC
 
-  /**
-   * A data-flow node that is an application of a cryptographic algorithm. For example,
-   * encryption, decryption, signature-validation.
-   *
-   * Extend this class to refine existing API models. If you want to model new APIs,
-   * extend `CryptographicOperation::Range` instead.
-   */
-  class CryptographicOperation extends SC::CryptographicOperation instanceof CryptographicOperation::Range
-  { }
+  final class CryptographicOperation = SC:: CryptographicOperation;
 
   class EncryptionAlgorithm = SC::EncryptionAlgorithm;
 

rust/ql/lib/codeql/rust/frameworks/RustCrypto.qll

@@ -16,7 +16,7 @@ private string simplifyAlgorithmName(string algorithmName) {
  * An operation that initializes a cipher through the `cipher::KeyInit` or
  * `cipher::KeyIvInit` trait, for example `Des::new` or `cbc::Encryptor<des::Des>::new`.
  */
-class StreamCipherInit extends Cryptography::CryptographicOperation::Range, DataFlow::Node {
+class StreamCipherInit extends Cryptography::CryptographicOperation::Range {
   string algorithmName;
 
   StreamCipherInit() {