fix issue with try in parser, improve parse error message

tests/ErrMsg.newt

@@ -0,0 +1,14 @@
+module ErrMsg
+
+import Prelude
+
+infixl 5 _$$_
+
+_$$_ : Nat → (Nat → Nat) → Nat
+a $$ b = a + b a
+
+-- Say something other than expected record
+-- Why do we get there? shouldn't the progress made by parseDef short circuit the <|>?
+blah : Nat → Nat
+blah x = x $$ $ \ y => y
+

tests/ErrMsg.newt.fail

@@ -0,0 +1,6 @@
+*** Process tests/ErrMsg.newt
+module Prelude
+module ErrMsg
+ERROR at tests/ErrMsg.newt:13:15--13:16: trailing operator
+
+Compile failed