Fix typo in `numberOfFiles` metric description

Change-Id: I25bc41974981e150f35f84dae29654dab383969e

src/main/java/com/googlesource/gerrit/plugins/gitrepometrics/collectors/FSMetricsCollector.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/gitrepometrics/collectors/FSMetricsCollector.java b/src/main/java/com/googlesource/gerrit/plugins/gitrepometrics/collectors/FSMetricsCollector.java
index 7d84061..bbbb7a4 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/gitrepometrics/collectors/FSMetricsCollector.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/gitrepometrics/collectors/FSMetricsCollector.java
@@ -80,7 +80,7 @@
   protected static final GitRepoMetric numberOfDirectories =
       new GitRepoMetric("numberOfDirectories", "Number of directories on filesystem", "Count");
   protected static final GitRepoMetric numberOfFiles =
-      new GitRepoMetric("numberOfFiles", "Number of directories on filesystem", "Count");
+      new GitRepoMetric("numberOfFiles", "Number of files on filesystem", "Count");
   private static final GitRepoMetric collectionTime =
       new GitRepoMetric(
           "fsMetricsCollectionTime", "Timestamp at which metrics were collected", "Milliseconds");