Fix a comment.
diff --git a/include/jemalloc/internal/arena.h b/include/jemalloc/internal/arena.h
index f972e8b..cb015ee 100644
--- a/include/jemalloc/internal/arena.h
+++ b/include/jemalloc/internal/arena.h
@@ -54,7 +54,7 @@
 	 * Run address (or size) and various flags are stored together.  The bit
 	 * layout looks like (assuming 32-bit system):
 	 *
-	 *   ???????? ???????? ???nnnnn nnndulma
+	 *   ???????? ???????? ???nnnnn nnndumla
 	 *
 	 * ? : Unallocated: Run address for first/last pages, unset for internal
 	 *                  pages.