Update introduction.mdx

Signed-off-by: tcaldwell-x <tcaldwell@twitter.com>

Author: tcaldwell-x

x-api/activity/introduction.mdx

@@ -32,7 +32,7 @@ Currenrtly, X Activity API supports the following profile update events, shown h
 | Profile | `ProfileBannerUpdate` | Fired when a user updates their profile banner |
 | Profile | `ProfileGeoUpdate` | Fired when a user updates their profile location |
 | Profile | `ProfileUrlUpdate` | Fired when a user updates their profile website URL |
-| Profile | `ProfileScreennameUpdate` | Fired when a user updates their username |
+| Profile | `ProfileScreennameUpdate` | Fired when a user updates their display name |
 | Profile | `ProfileVerifiedBadgeUpdate` | Fired when a user updates their verified badge |
 | Profile | `ProfileHandleUpdate` | Fired when a user updates their handle |