Fix delete -> del in docs on typescript

Closes GH-1343/

Reviewed-by: Christian Murphy <[email protected]>
Reviewed-by: Titus Wormer <[email protected]>

Author: freeshineit

docs/advanced/typescript.mdx

@@ -15,7 +15,7 @@ declare module '@mdx-js/react' {
     | 'a'
     | 'blockquote'
     | 'code'
-    | 'delete'
+    | 'del'
     | 'em'
     | 'h1'
     | 'h2'