ProjectWatchInfo: Suppress false positive OrphanedFormatString warning

In change I259033fe we enabled the OrphanedFormatString check as an
error by error prone. This check looks for passing a string that
contains format specifiers to a method that does not perform string
formatting, as this is usually a mistake. We suppress the warning here
since it is done intentionally (i.e. this is no mistake).

Change-Id: Ic171f023844b658eee8e1eca503551f214e4d278
diff --git a/java/com/google/gerrit/extensions/client/ProjectWatchInfo.java b/java/com/google/gerrit/extensions/client/ProjectWatchInfo.java
index 3c20ff7..8f5af76 100644
--- a/java/com/google/gerrit/extensions/client/ProjectWatchInfo.java
+++ b/java/com/google/gerrit/extensions/client/ProjectWatchInfo.java
@@ -54,6 +54,7 @@
   }
 
   @Override
+  @SuppressWarnings("OrphanedFormatString")
   public String toString() {
     StringBuilder b = new StringBuilder();
     b.append(project);