fixes and improvements

• (Spring Boot) fixed: Spring Boot Tools slow down code complete (#808)
• (Language Server) fixed: Copied files should retain copyright ownership (#807)

known issues

• (Eclipse): Due to additional third-party add-ons being installed by default into the Spring Tools 4 for Eclipse distribution, the Maven POM file editor still uses the old XML editor when selecting the source page of that editor (instead of the new, XML language server based one). You can workaround that by manually opening the pom.xml file with Open With and select the Generic Editor.