Update test-links.md

URLs can't contain angled brackets

doc/developer/tests/test-links.md

@@ -39,6 +39,8 @@ http://
 @example.com  
 ./make-compiled-client.sh  
 test.:test  
+https://<your-mattermost-url>/signup/gitlab  
+https://your-mattermost-url>/signup/gitlab  
 
 #### Only the links within these sentences should auto-link: