add doc regarding spring boot devtools and restart classloader issues

[nisrael]

As described in the changes there was a classloader issue with spring boot devtools. I forked your spring boot 3 example, added spring boot devtools and the workaround; https://github.com/nisrael/specification-arg-resolver-example-springboot3 To trigger the exception comment out the line in src/main/resources/META-INF/spring-devtools.properties.