MINOR: Add info about removed JavadocMethod check to storm_checkstyle.xml comment (#3086)

diff --git a/storm-checkstyle/src/main/resources/storm/storm_checkstyle.xml b/storm-checkstyle/src/main/resources/storm/storm_checkstyle.xml
index d1497c8..4b20a6f 100644
--- a/storm-checkstyle/src/main/resources/storm/storm_checkstyle.xml
+++ b/storm-checkstyle/src/main/resources/storm/storm_checkstyle.xml
@@ -27,6 +27,7 @@
     It has been slightly modified for use in Apache Storm, as follows:
       * 4 space indents instead of 2
       * line-length limit is 140 instead of 100
+      * removed JavadocMethod
     Once checkstyle has the ability to override selected configuration elements from within the Maven
     pom.xml file, then we can remove this file in favor of overriding the provided google_checks.xml file.
     See this issue to track that functionality: