Bugfix when linking to 1st comment on secondary pages of thread

pkg/models/comment.go

@@ -172,6 +172,14 @@ func FindPageByComment(user *User, comment *Comment, pageSize int) (int, error)
 	for i, cid := range allCommentIDs {
 		if cid == comment.ID {
 			var page = int(math.Ceil(float64(i) / float64(pageSize)))
+
+			// If the comment index is an equal multiple of the page size
+			// (e.g. comment #20 is the 1st comment on page 2, since 0-19 is page 1),
+			// account for an off-by-one error.
+			if i%pageSize == 0 {
+				page++
+			}
+
 			if page == 0 {
 				page = 1
 			}