more precise comment

src/main/groovy/com/avast/gradle/dockercompose/ServiceHost.groovy

@@ -2,7 +2,7 @@ package com.avast.gradle.dockercompose
 
 import groovy.transform.Immutable
 
-// @Immutable annotation generates a code that uses classes from Groovy library.
+// @Immutable annotation generates a code that uses ImmutableASTTransformation class from Groovy library.
 // When compiling for Gradle 5+ (so Groovy 2.5+) then the generated code uses a new method that was added in Groovy 2.5.
 // Therefore this method is not available in Groovy 2.4, so in Gradle 4.x.
 // So we disabled the @Immutable annotations because we want to support also Gradle 4.x users.