Update PluralKit message tag (#362)

Changes [BOT] to [APP] as a reflection of recent changes to how that tag is presented to users.

Signed-off-by: SympathyTea <[email protected]>

tags/pluralkit.md

@@ -7,7 +7,7 @@ Plurality is the existence of multiple self-aware entities inside the same brain
 
 Each member of a system/collective (group residing inside the same physical brain) is an individual person, so please treat them as such.
 
-On Discord, some systems may use [PluralKit](https://pluralkit.me/) to make their message appear with the correct profile, resulting in a `[BOT]` tag.
+On Discord, some systems may use [PluralKit](https://pluralkit.me/) to make their message appear with the correct profile, resulting in a `[APP]` tag.
 
 For more information about plurality, we recommend [More Than One](https://morethanone.info/) for a useful overview.