[Bug]: Header comments are removed

### Describe the bug

The `//` comments are removed by default. This violates the principle of least surprise, IMO.

### Source code you are trying to analyze/transform

```
cd /tmp
git clone https://github.com/DaveJarvis/nts
```

### Source code for your Spoon processing

```Java
import spoon.Launcher;
import spoon.refactoring.Refactoring;
import spoon.support.sniper.SniperJavaPrettyPrinter;

import java.io.File;
import java.util.regex.Pattern;

public class App {
public static void main( final String[] args ) {
final var outputDir = new File("/tmp/nts-new");
final var spoon = new Launcher();

final var env = spoon.getEnvironment();
env.setPrettyPrinterCreator(
() -> new SniperJavaPrettyPrinter( env )
);
env.setAutoImports( true );

spoon.setSourceOutputDirectory( outputDir );

spoon.addInputResource( "/tmp/nts/app/src/main/java/nts/app" );
spoon.addInputResource( "/tmp/nts/dvi/src/main/java/nts/dvi" );
spoon.addInputResource( "/tmp/nts/png/src/main/java/nts/png" );
spoon.addInputResource( "/tmp/nts/svg/src/main/java/nts/svg" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/align" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/base" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/builder" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/command" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/hyph" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/io" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/math" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/noad" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/node" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/render" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/tex" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/tfm" );
spoon.addInputResource( "/tmp/nts/tex/src/main/java/nts/typo" );
spoon.addInputResource( "/tmp/nts/tex/src/test/java/nts/io" );

final var model = spoon.buildModel();
final var p = Pattern.compile( "^(?!Kt).*" );

for( final var clazz : model.getAllTypes() ) {
final var name = clazz.getSimpleName();
final var m = p.matcher( name );

if( m.matches() ) {
final var newName = "Kt" + name;

System.out.println( "rename " + name + " to " + newName );
Refactoring.changeTypeName( clazz, newName );
}
}

if( outputDir.exists() || outputDir.mkdirs() ) {
spoon.prettyprint();
}
}
}
```

### Actual output

```Java
package nts.align;public class KtEndv extends KtBuilderCommand {

public final void addOn(KtLog log) {
log.add("end of alignment template");
}
}
```

### Expected output

```Java
// Copyright 2001 by
// DANTE e.V. and any individual authors listed elsewhere in this file.
//
// This file is part of the NTS system.
// ------------------------------------
//
// It may be distributed and/or modified under the
// conditions of the NTS Public License (NTSPL), either version 1.0
// of this license or (at your option) any later version.
// The latest version of this license is in
// http://www.dante.de/projects/nts/ntspl.txt
// and version 1.0 or later is part of all distributions of NTS
// version 1.0-beta or later.
//
// The list of all files belonging to the NTS distribution is given in
// the file `manifest.txt'.
//
// Filename: nts/align/Endv.java
// $Id: Endv.java,v 1.1.1.1 2001/03/12 21:42:18 ksk Exp $
package nts.align;

import nts.io.KtLog;
import nts.typo.KtBuilderCommand;

public class KtEndv extends KtBuilderCommand {

public final void addOn(KtLog log) {
log.add("end of alignment template");
}
}
```

### Spoon Version

Latest

### JVM Version

18

### What operating system are you using?

Linux

Start with the SniperJavaPrettyPrinter entry point shown in the reproduction and run the supplied App against the NTS sources. Trace how header `//` comments are handled during pretty-printing, then verify that the generated Endv.java retains the original comments and formatting shown in the expected output.

Written by the indexing model from the issue text.