Polls don't display own votes

[tbroyer]

After one votes on a poll, it's not possible to know which option(s) were chosen. This is particularly interesting when displaying expired poll notifications, when you don't necessarily remember which option(s) you chose.

The information is available in the own_votes property: https://docs.joinmastodon.org/entities/Poll/#own_votes

Mastodon displays this with a :heavy_check_mark: next to the voted option.