Update Html.hs (#17)

Author: dmjio

src/Miso/From/Html.hs

@@ -119,6 +119,10 @@ instance Show HTMLAttr where
       , T.unpack v
       , "\" "
       ]
+  show (HTMLAttr x@(T.isPrefixOf "data-" -> True) Nothing) =
+    case T.stripPrefix "data-" x of
+      Just rest -> "data_ " <> "\"" <> T.unpack rest <> "\"" <> " \"\""
+      Nothing -> T.unpack x
   show (HTMLAttr "checked" Nothing) =
     "checked_ True"
   show (HTMLAttr k Nothing) =