This PR fixes indentation by replacing four spaces with a tab in Kotlin source files to align with the project's .editorconfig file:
https://github.com/spring-projects/spring-framework/blob/c6126b2033a72e7d0f555d0f49cf1145c87bc036/.editorconfig#L6-L8
Comment From: sdeleuze
Adapted for 6.1.x and merged with main, thanks!