message: fix post slider controls disappearing
diff: </div>
  <template v-if="post.media.length > 1">
  - <div
  - class="-prev"
  - :class="{ '-hide': page < post.media.length }"
  - @click.stop="goPrev"
  - >
  + <div class="-prev" :class="{ '-hide': page === 1 }" @click.stop="goPrev">
  <app-jolticon icon="chevron-left" />
  </div>
  - <div class="-next" :class="{ '-hide': page > 1 }" @click.stop="goNext">
  + <div
  + class="-next"
  + :class="{ '-hide': page === post.media.length }"
  + @click.stop="goNext"
  + >
  <app-jolticon icon="chevron-right" />
  </div>
  </template>
  