Expanded javadoc for ConfigLoader

Change-Id: I84c7d7680300d4c92daed8b9072114bf8a4a30c1
diff --git a/src/main/java/com/googlesource/gerrit/plugins/automerger/ConfigLoader.java b/src/main/java/com/googlesource/gerrit/plugins/automerger/ConfigLoader.java
index 127ff17..e74e5b2 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/automerger/ConfigLoader.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/automerger/ConfigLoader.java
@@ -46,10 +46,13 @@
   private volatile LoadedConfig config;
 
   /**
-   * Initializer to read the config options of the config, and load the configuration based on it.
+   * Read static configuration from config_keys.yaml and try to load initial dynamic configuration.
+   *
+   * <p>If loading dynamic configuration fails, logs and treats configuration as empty. Callers can
+   * call {@link loadConfig} to retry.
    *
    * @param gApi API to access gerrit information.
-   * @throws IOException
+   * @throws IOException if reading config_keys.yaml failed
    */
   @Inject
   public ConfigLoader(GerritApi gApi) throws IOException {