There's still a flaw where it is not detected as no curly when the phx-no-curly-interpolation is on another line.

I looked into this and came to the conclusion that it's not possible to reasonably do this, as Textmate grammars cannot have multiline begin patterns. Therefore, as soon as someone does

<p
  phx-no-curly-interpolation
  class=""
  ...
>...</p>

we would not be able to reasonable detect this.

Closing in favor of #28.