docs: Update contributors, marking @SlexAxton as a "Former Contributor" (#437)

Author: XM5jDcsHTyGJtQqlCi

CONTRIBUTING.md

@@ -5,7 +5,9 @@ If something is not clear and you have looked at our [documentation site](https:
 
 Messageformat is an [OpenJS Foundation](https://openjsf.org) project, and we follow its [Code of Conduct](https://code-of-conduct.openjsf.org/).
 
-Our current governance is pretty straightforward; our core contributors [Alex Sexton](https://github.com/SlexAxton) and [Eemeli Aro](https://github.com/eemeli) are in charge. If you'd like to have a say too, active participation is a really good way forward.
+Our current governance is pretty straightforward;
+our core contributor [Eemeli Aro](https://github.com/eemeli) is in charge.
+If you'd like to have a say too, active participation is a really good way forward.
 
 ## Getting Started
 

docs/about.md

@@ -79,5 +79,8 @@ See [CONTRIBUTING.md](https://github.com/messageformat/messageformat/blob/main/C
 
 ## Core Contributors
 
+- Eemeli Aro - [@eemeli@mefi.social ](https://mefi.social/@eemeli) - [github.com/eemeli](https://github.com/eemeli)
+
+## Former Contributors
+
 - Alex Sexton - [@SlexAxton](http://twitter.com/SlexAxton) - [alexsexton.com](http://alexsexton.com/)
-- Eemeli Aro - [@eemeli_aro](http://twitter.com/eemeli_aro) - [github.com/eemeli](https://github.com/eemeli)