Questions with comments don't parse

[fuhrmanator]

There are several cases with comments that don't parse properly, according to the validator:

https://fuhrmanator.github.io/GIFT-grammar-PEG.js/editor/editor.html?text=JOr1IiH044NtESK7oSvaHd805sxLqOM2op8fniQcQkogde2Yz_4SNinknPZUDBpY_NUREKOs7CFFvqdpaJllL40P5oGqqJdUq7oW7OP-Q76bukdhao8QB73dJZEjoJt9MBVIB-pEjjiMrppZGTFpcjrG2eRcf3nS4XvLX5421nLZiFb_yVIlmxxUVsys6znvYC7u5P5XOIzS2WVD2QxPsGgsPTNwQkm4amP7a2cyP4xLhCR8uhHdJ8pnYSfbyVfl

Quelles villes trouve-t-on au Canada? { 
~ %33.3% Montréal 
 ~ %33.3% Ottawa 
 ~ %33.3% Vancouver 
 ~ %-100% New York 
 ~ %-100% Paris 
#### La bonne réponse est Montréal, Ottawa et Vancouver 
}
// Utilisez le signe ~ pour toutes les réponses.
// On doit indiquer le pourcentage de chaque réponse.

From the blog on GIFT at https://fuhrmanator.github.io/posts/markdown-in-gift/

https://fuhrmanator.github.io/GIFT-grammar-PEG.js/editor/editor.html?text=VSz1Jkj030RWVKxnBzl5Uzq7iK0z0aWi25BSYKcYpDZHUAfGLUKid8MJaMbITSV2A_lpRvVbNXl6mQiR3Bt04WUGD7FPnD7AidWB58T69talTZkyKfHUsXAfuyYWkKm3GrJ-7IBJC3TX8pasRBpg0DyFkHq3-RMnBVOQHi-9ynPygFSwPVTo6ldPnNvCS9xCO8e-eIC38N3gj85Gu0PrgpMAr542ESTZoXEMOjv2iJq6bhJyuISw6IAdOnH3YaV-NrHIrtKb_3bgl4KzeJfNylCDO7xJhGTMKbskqyMv0837bRQweQfS4xTtkkHSOnuMk-Xil-xsTkcVChlBBm00

::Code blocks in stem and answers::
[markdown]
// Warning: there are some non-breaking spaces (look like normal spaces)
Complete the following TypeScript class so it has a method named `go` 
that accepts a string argument and always returns true.
\n```\nexport class A \{\n    // complete\n\}\n```
{
    =\n```\ngo(a\: string) \{\n    return true;\n\}\n\n```
    ~\n```\ngo(string a) \{\n    return true;\n\}\n```
}