Add shared-dict guide to hex docs

Author: benoitc

rebar.config

@@ -50,6 +50,7 @@
         <<"docs/buffer.md">>,
         <<"docs/streaming.md">>,
         <<"docs/memory.md">>,
+        <<"docs/shared-dict.md">>,
         <<"docs/logging.md">>,
         <<"docs/scalability.md">>,
         <<"docs/threading.md">>,
@@ -77,6 +78,7 @@
             <<"docs/buffer.md">>,
             <<"docs/streaming.md">>,
             <<"docs/memory.md">>,
+            <<"docs/shared-dict.md">>,
             <<"docs/logging.md">>
         ]},
         {<<"Advanced">>, [