Rust: remove //generated headers

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

@@ -1,4 +1,3 @@
-// generated by codegen, remove this comment if you wish to edit this file
 /**
  * This module provides a hand-modifiable wrapper around the generated class `BlockExpr`.
  *
@@ -12,6 +11,7 @@ private import codeql.rust.elements.internal.generated.BlockExpr
  * be referenced directly.
  */
 module Impl {
+  // the following QLdoc is generated: if you need to edit it, do it in the schema file
   /**
    * A block expression. For example:
    * ```rust

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

@@ -1,4 +1,3 @@
-// generated by codegen, remove this comment if you wish to edit this file
 /**
  * This module provides a hand-modifiable wrapper around the generated class `IfExpr`.
  *
@@ -12,6 +11,7 @@ private import codeql.rust.elements.internal.generated.IfExpr
  * be referenced directly.
  */
 module Impl {
+  // the following QLdoc is generated: if you need to edit it, do it in the schema file
   /**
    * An `if` expression. For example:
    * ```rust

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

@@ -1,4 +1,3 @@
-// generated by codegen, remove this comment if you wish to edit this file
 /**
  * This module provides a hand-modifiable wrapper around the generated class `MacroExpr`.
  *
@@ -13,6 +12,7 @@ private import codeql.rust.elements.MacroStmts
  * be referenced directly.
  */
 module Impl {
+  // the following QLdoc is generated: if you need to edit it, do it in the schema file
   /**
    * A MacroExpr. For example:
    * ```rust