comments: set default comment threshold to -8.

* Set the default comment threshold to -8. This means that comments are
  hidden at -8 or lower and greyed out at -4 or lower.

* Reset the comment threshold to -8 for anyone with a threshold greater
  than -8. For reference, only about ~3100 users had a non-default
  threshold. About 1600 of those had their threshold reset to -8.

* Change the comment threshold to a less-than-or-equal comparison
  instead of a less-than comparsion. This means that a threshold of 0
  before is the same as a threshold of -1 now. Since everyone's
  thresholds were reset, this only affects people whose thresholds were
  already less than -8, which is so low that the difference shouldn't
  matter much.

* Set the maximum comment threshold to 5. For reference, less than 1% of
  comments have a score greater than 5.

* Set the minimum comment threshold to -100. For reference, the most
  downvoted comment has a score of -60.

CHANGELOG.md

@@ -18,6 +18,19 @@
 * You can now see when a post has deleted comments. Deleted comments are now
   replaced with the word `[deleted]`, instead of being completely hidden.
 
+* The way downvoted comments work has changed. Instead of comments being
+  completely hidden when they get downvoted, and having to click "Show X hidden
+  comments" to see them, now they get collapsed and marked as `[hidden]`, and
+  you click the comment itself to unhide it.
+
+* The default comment threshold has been lowered to -8. This means that
+  comments are now hidden at -8 and greyed out at -4. If your threshold was
+  higher than this, it has been reset to -8. You can go to your settings to
+  change this.
+
+* The maximum comment threshold is now 5 and the minumum threshold is now
+  -100. You can't set your threshold any higher or lower than this.
+
 ### API Changes
 
 * Deleted comments now have some of their fields hidden in the API. The