Expose the manifest type

Note - dialyzer is unhappy with this being opaque :/

Author: the-mikedavis

src/osiris_log.erl

@@ -463,14 +463,16 @@
         }).
 
 -opaque state() :: #?MODULE{}.
+-type manifest() :: #manifest{}.
 
 -export_type([state/0,
               chunk_iterator/0,
               range/0,
               config/0,
               counter_spec/0,
               transport/0,
-              chunk_type/0]).
+              chunk_type/0,
+              manifest/0]).
 
 -spec directory(osiris:config() | list()) -> file:filename_all().
 directory(#{name := Name, dir := Dir}) ->