Update proposed_code_of_conduct.md

Added Facebook and Mozilla CoC as inspirations for expanded scope (to external spaces impact on community health)

proposed_code_of_conduct.md

@@ -82,6 +82,10 @@ version 2.0, available at
 Community Impact Guidelines were inspired by
 [Mozilla's code of conduct enforcement ladder][Mozilla CoC].
 
+Expanding scope to external influence on community health, inspired by
+[Facebook's Code of Conduct](https://opensource.facebook.com/code-of-conduct) and
+[Mozilla's Community Participation Guidelines](https://www.mozilla.org/en-US/about/governance/policies/participation/)
+
 For answers to common questions about this code of conduct, see the FAQ at
 [https://www.contributor-covenant.org/faq][FAQ]. Translations are available
 at [https://www.contributor-covenant.org/translations][translations].