Update --new-model-addition.md

Motivate users to @-tag authors of models to increase visibility and expand the community

.github/ISSUE_TEMPLATE/--new-model-addition.md

@@ -7,17 +7,17 @@ assignees: ''
 
 ---
 
-# 🌟New model addition
+# 🌟 New model addition
 
 ## Model description
 
 <!-- Important information -->
 
-## Open Source status
+## Open source status
 
 * [ ] the model implementation is available: (give details)
 * [ ] the model weights are available: (give details)
-* [ ] who are the authors: (mention them)
+* [ ] who are the authors: (mention them, if possible by @gh-username)
 
 ## Additional context