Add hwtest 3DS command

The .hw hwtest is a bit verbose and is also intended to be sent
in #hardware, based on phrasing.

This command just links to the wiki article, which is what the tag did
before it was deleted.

Author: TophattedWasTaken

cogs/assistance-cmds/hwtest.3ds.md

@@ -0,0 +1,9 @@
+---
+title: 3DS Hardware Test
+url: https://wiki.hacks.guide/wiki/3DS:Hardware_test
+author.name: Wiki Contributors
+thumbnail-url: https://nintendohomebrew.com/assets/img/nhmemes/bigh.png
+help-desc: Links to a guide to test the RAM of a 3DS
+---
+
+Test RAM problems on 3DS