Apply spring java format

[koppor]

Follow-up to #672

I think spring-javaformat is our last chance if we don't want to configure our own rules. The plugin is automatically activated in IntelliJ. For the code style, see https://github.com/spring-projects/spring-framework/wiki/Code-Style

spaces instead of tabs are activated.

We still need

• Variable naming conventions
• Custom intellij rules for import statements

The source formatter does not fundamentally change your code. For example, it will not change the order of import statements. It is effectively limited to adding or removing whitespace and line feed

We need to accept that else starts on the "first" column. ("Kernighan and Ritchie style") -> https://github.com/spring-projects/spring-framework/wiki/Code-Style#block-like-constructs-kr-style

This is OK for me.

If this new coe style is OK, setup .git blame ignore - as outlined at JabRef#10646 (comment). Do a merge commit, not a squash-merge.

Steps to test

Open the code in IntelliJ

Mandatory checks

• I own the copyright of the code submitted and I license it under the MIT license
• [.] Change in CHANGELOG.md described in a way that is understandable for the average user (if change is visible to the user)
• [.] Tests created for changes (if applicable)
• [.] Manually tested changed features in running JabRef (always required)
• [.] Screenshots added in PR description (if change is visible to the user)
• [.] Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• [.] Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[calixtus]

This is not working for me.

takes wastes too much space:

worsens overview:

not working correctly with flow-style:

Is there another codestyle available in the spring utility?

[koppor]

The bad formatting was already posted 2023 at #663 (comment) - but I totally forgot about it.

[koppor]

note that google java format also cannot be used, because it does not support Markdown comments: google/google-java-format#1193

[koppor]

spotless is still no option: diffplug/spotless#2599

[koppor]

IntelliJ can use Eclipse formatter: https://github.com/krasa/EclipseCodeFormatter