Improve some parse errors

test/contracts/indent_fail.aes

@@ -0,0 +1,3 @@
+contract IndentFail =
+  entrypoint twoSpace() = ()
+ entrypoint oneSpace() = ()

test/contracts/vclose.aes

@@ -0,0 +1,4 @@
+contract VClose =
+  entrypoint missing_bracket() =
+    let x = [1, 2, 3
+  entrypoint bar() = ()

test/contracts/vsemi.aes

@@ -0,0 +1,3 @@
+contract VSemi =
+  record missing_brace = { x : int
+  entrypoint foo() = ()