Add @FormatMethod to StalenessCheckResult#stale

This surfaced in a Google-internal error prone check.

This commit adds the error prone check to the list of checks
we run.

Change-Id: I7703c0b13dd00982d5c58df980721ee0287edda8
diff --git a/java/com/google/gerrit/server/BUILD b/java/com/google/gerrit/server/BUILD
index 979ab6f..45d037a 100644
--- a/java/com/google/gerrit/server/BUILD
+++ b/java/com/google/gerrit/server/BUILD
@@ -112,6 +112,7 @@
         "//lib/commons:lang",
         "//lib/commons:net",
         "//lib/commons:validator",
+        "//lib/errorprone:annotations",
         "//lib/flogger:api",
         "//lib/guice",
         "//lib/guice:guice-assistedinject",
diff --git a/java/com/google/gerrit/server/index/StalenessCheckResult.java b/java/com/google/gerrit/server/index/StalenessCheckResult.java
index cd3f592..fe35e6e 100644
--- a/java/com/google/gerrit/server/index/StalenessCheckResult.java
+++ b/java/com/google/gerrit/server/index/StalenessCheckResult.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.server.index;
 
 import com.google.auto.value.AutoValue;
+import com.google.errorprone.annotations.FormatMethod;
 import java.util.Optional;
 
 /** Structured result of a staleness check. */
@@ -29,6 +30,7 @@
     return new AutoValue_StalenessCheckResult(true, Optional.of(reason));
   }
 
+  @FormatMethod
   public static StalenessCheckResult stale(String reason, Object... args) {
     return stale(String.format(reason, args));
   }
diff --git a/tools/BUILD b/tools/BUILD
index 5531c3e..f0a4ffa 100644
--- a/tools/BUILD
+++ b/tools/BUILD
@@ -53,6 +53,7 @@
         "-Xep:ExpectedExceptionChecker:ERROR",
         "-Xep:Finally:ERROR",
         "-Xep:FloatingPointLiteralPrecision:ERROR",
+        "-Xep:FormatStringAnnotation:ERROR",
         "-Xep:FragmentInjection:ERROR",
         "-Xep:FragmentNotInstantiable:ERROR",
         "-Xep:FunctionalInterfaceClash:ERROR",