Add help entry for Share button

Change-Id: I11eb7d93731192ead9e17aeb495bcb3faf6b4356
Reviewed-on: https://fuchsia-review.googlesource.com/c/fidlbolt/+/761603
Reviewed-by: Yifei Teng <yifeit@google.com>
diff --git a/frontend/src/elm/Main.elm b/frontend/src/elm/Main.elm
index a6c6487..6c515a2 100644
--- a/frontend/src/elm/Main.elm
+++ b/frontend/src/elm/Main.elm
@@ -468,6 +468,15 @@
                 ]
             , Html.li []
                 [ text "Click the "
+                , bold "Share"
+                , text " "
+                , multiline """
+button to generate a link you can share with other people. This link saves
+everything from the FIDL editor.
+"""
+                ]
+            , Html.li []
+                [ text "Click the "
                 , bold "Settings"
                 , text " "
                 , multiline """