HeaderFormatter: Remove unused appendChangeId method

Change-Id: I0acf1ea301dfc02e3342e4942dffeb580cc86489
Signed-off-by: Edwin Kempin <ekempin@google.com>

src/main/java/com/googlesource/gerrit/plugins/reviewnotes/HeaderFormatter.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/HeaderFormatter.java b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/HeaderFormatter.java
index 17863a2..2572309 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/HeaderFormatter.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/HeaderFormatter.java
@@ -48,10 +48,6 @@
     this.anonymousCowardName = anonymousCowardName;
   }
 
-  void appendChangeId(Change.Key changeKey) {
-    sb.append("Change-Id: ").append(changeKey.get()).append("\n");
-  }
-
   /**
    * Appends a header for an approval.
    *