Parse error when evaluating brace-enclosed body

[tsandall]

The new syntax allows for brace-enclosed bodies to separate expressions with newlines.

{
   p[x]
   q[x]
}

Is equivalent to p[x], q[x].

Currently, the grammar only allows brace-enclosed bodies for rules. They are not supported on their own:

> {
|   p[x]
|   q[x]
| }
|
error: 1 error occurred: 2:0: no match found, unexpected '{'

Build info:

> data
{
  "repl": {
    "version": {
      "BuildCommit": "fddedd3",
      "BuildHostname": "testing-gce-fc0690d8-894b-425b-b34e-14af86b24eef",
      "BuildTimestamp": "2017-02-09T00:39:35Z",
      "Version": "0.4.2-dev"
    }
  }
}