SOLR-9030: Added a code comment as to why we use Integer.MAX_VALUE instead of -1

(cherry picked from commit 827573b1a7bda2ae853f03c518f313e5992c1a7c)

solr/solrj/src/java/org/apache/solr/common/cloud/DocCollection.java

@@ -66,6 +66,7 @@ public class DocCollection extends ZkNodeProps {
    */
   public DocCollection(String name, Map<String, Slice> slices, Map<String, Object> props, DocRouter router, int zkVersion, String znode) {
     super(props==null ? props = new HashMap<>() : props);
+    // -1 means any version in ZK CAS, so we choose Integer.MAX_VALUE instead to avoid accidental overwrites
     this.znodeVersion = zkVersion == -1 ? Integer.MAX_VALUE : zkVersion;
     this.name = name;