changed heading text to fix linking issue (#4590)

Author: imatwawana

src/docs/product/integrations/integration-platform/webhooks.mdx

@@ -117,7 +117,7 @@ You cannot set up a custom payload. Instead, we suggest setting up a server/serv
 
 ## Event Types
 
-### [Un]Installation
+### Installation & Uninstallation {#uninstallation}
 
 `'Sentry-Hook-Resource': 'installation'`