Rust: Make usage of Impl more consistent with other Impl modules.

Author: geoffw0

rust/ql/lib/codeql/rust/elements/Operation.qll

@@ -2,7 +2,7 @@
  * Provides classes for operations.
  */
 
-import internal.OperationImpl::Impl as OperationImpl
+private import internal.OperationImpl
 private import codeql.rust.elements.internal.ExprImpl::Impl as ExprImpl
 
-final class Operation = OperationImpl::Operation;
+final class Operation = Impl::Operation;

rust/ql/lib/codeql/rust/elements/internal/BinaryExprImpl.qll

@@ -5,7 +5,7 @@
  */
 
 private import codeql.rust.elements.internal.generated.BinaryExpr
-private import codeql.rust.elements.Operation::OperationImpl as OperationImpl
+private import codeql.rust.elements.internal.OperationImpl::Impl as OperationImpl
 
 /**
  * INTERNAL: This module contains the customizable definition of `BinaryExpr` and should not

rust/ql/lib/codeql/rust/elements/internal/PrefixExprImpl.qll

@@ -5,7 +5,7 @@
  */
 
 private import codeql.rust.elements.internal.generated.PrefixExpr
-private import codeql.rust.elements.Operation::OperationImpl as OperationImpl
+private import codeql.rust.elements.internal.OperationImpl::Impl as OperationImpl
 
 /**
  * INTERNAL: This module contains the customizable definition of `PrefixExpr` and should not