title: comment sql queries in liquibase formatted sql files
body: <p>I have liquibase formatted sql file containing following changesets in which sql queries are being commented out</p>
  
  <pre><code>--liquibase formatted sql
  
  --changeset harv:1
  --comment test
  --update table set col=null;
  
  --changeset harv:2
  --comment test
  --update table set col1=null;
  </code></pre>
  
  <p>when I run liquibase on oracle database theses queries are not being executed since I commented them but entries are being made into databasechangelog table that these changesets are executed.</p>
  
  <p>Is this the proper way to comment sql queries? If it is why is liquibase making entries in databasechangelog table marking these changesets as executed?</p>