fluent 0.13.0

• Support Fluent Syntax 1.0.

  Syntax 1.0 is the same as Syntax 0.9, and the support for it in this
  release continues to be the same as in fluent 0.12. This note is meant
  to clearly indicate that fluent supports the first stable version of
  the Syntax specification.

• Improve the fallback string in case of expression errors.

  Unresolved expressions are now printed with braces around them, e.g.
  {missing} rather than missing (#368). References to missing message
  attributes now fall back to {messageId.attributeName} (#370).

• Remove the ftl dedent helper.

  The ftl dedent helper has moved to its own package, @fluent/dedent.
  Note that its behavior has changed slightly, too. See the
  README for details.