Merging tool for code style XML files, remove formatter version lock

[WolframPfeifer]

This is a refined version of #3498. It removes the Eclipse formatter version lock (not needed any more, since the bug in the formatter has been fixed). In addition, it adds a small Java utility that can be used to merge two XML code style files.

New tool for merging Eclipse code style files: Every few versions, the Eclipse formatter comes with a few new options for configuration. It was a very annoying to find out which keys are missing in the style file scripts/tools/checkstyle/keyCodeStyle.xml, so this PR adds a small tool to merge two such files. It resides in the same directory as the style file.

The easiest way to add the new options to our style file is to open the Eclipse GUI and export the style (in this example to scripts/tools/checkstyle/eclipse.xml). The styles could then be merged like this:

cd scripts/tools/checkstyle
cp keyCodeStyle.xml keyCodeStyle_old.xml
# optionally, the flag --overwriteValues can be used to replace all the old values with those set in eclipse.xml
java CodeStyleMerger.java keyCodeStyle_old.xml eclipse.xml keyCodeStyle.xml

Afterwards, since the tool makes sure to sort the entries by the keys, it can be easily seen via git diff keyCodeStyle.xml what has changes. Optionally, you can now set the values of the new keys (by manually editing the file).

In contrast to #3498, the formatter is configured to not touch code blocks in comments.

Intended Change

• removes formatter version lock
• adds tool for merging style files
• slightly changes style (disable formatting of code blocks in comments/JavaDoc)
• applies the new style

Type of pull request

• New feature (non-breaking change which adds functionality)
• There are changes to the deployment/CI infrastructure (gradle, github, ...): Small change of the code style
• Other: There is a new tool for developers

Ensuring quality

• I made sure that introduced/changed code is well documented (javadoc and inline comments).

The contributions within this pull request are licensed under GPLv2 (only) for inclusion in KeY.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud