javadoc: Mention midx order in the javadoc

Link: https://review.gerrithub.io/id/I84b5f0163ca7725de248afcc26f8f9246a6a6964

Author: ifradeo

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidx.java

@@ -90,9 +90,10 @@ protected DfsPackFileMidx(DfsBlockCache cache, DfsPackDescription desc) {
 	public abstract DfsPackFileMidx getMultipackIndexBase();
 
 	/**
-	 * Packs indexed by this multipack index (base NOT included)
+	 * Packs indexed by this multipack index (base NOT included) in midx order.
 	 *
-	 * @return packs indexed by this multipack index
+	 * @return packs indexed by this multipack index in the order used inside
+	 *         the midx.
 	 */
 	public abstract List<DfsPackFile> getCoveredPacks();
 

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/midx/PackIndexMerger.java

@@ -53,7 +53,8 @@ public class PackIndexMerger {
 	/**
 	 * Builder collecting the inputs for the merger.
 	 * <p>
-	 * Order matters. Packs will appear in the midx in the order they are added.
+	 * Order matters. In case of duplicates, the merger chooses the object in
+	 * the first pack it appears.
 	 */
 	public static class Builder {