spring-projectsGH-39732 Update description of virtual threads

Author: Lukas Dohmen

spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-application.adoc

@@ -387,8 +387,8 @@ If you're running on Java 21 or up, you can enable virtual threads by setting th
 Before turning on this option for your application, you should consider https://docs.oracle.com/en/java/javase/21/core/virtual-threads.html[reading the official Java virtual threads documentation].
 In some cases, applications can experience lower throughput because of "Pinned Virtual Threads"; this page also explains how to detect such cases with JDK Flight Recorder or the `jcmd` CLI.
 
-WARNING: One side effect of virtual threads is that these threads are daemon threads.
-A JVM will exit if there are no non-daemon threads.
+WARNING: One side effect of virtual threads is that they are daemon threads.
+A JVM will exit if all of its threads are daemon threads.
 This behavior can be a problem when you rely on, e.g. `@Scheduled` beans to keep your application alive.
 If you use virtual threads, the scheduler thread is a virtual thread and therefore a daemon thread and won't keep the JVM alive.
 This does not only affect scheduling, but can be the case with other technologies, too!