core&ui: add discussion history (#450)

Co-authored-by: 无限UCW <45730483+wuxianucw@users.noreply.github.com>
Co-authored-by: undefined <i@undefined.moe>

packages/ui-default/components/discussion/comments.page.styl

@@ -48,6 +48,10 @@ $downvote-color = red
   float: left
   margin-bottom: rem(5px)
 
+  .history
+    float: right
+    margin-left: rem(5px)
+
 .dczcomments__operations
   font-size: rem($font-size)
   float: right