Fix server error rendering comments

[tal66]

hi, this fixes #712.

the problem was here
specifically with markdownify

and originated here

[tal66]

i ain't a js expert, but it seems this list should also be fixed to 9,007,199,254,740,991

Edit: i take it back. shouldn't rely on medium articles..

[geekygirlsarah]

Hey @tal66, I appreciate you jumping on this bug to solve it! Unfortunately I think @ulyssear barely beat you to it with #709. I'm going to close this since it's now a duplicate. I hope you're still willing to contribute to something else!