Document Microsoft's Remote extensions

Closes #1681

Author: nhooyr

doc/FAQ.md

@@ -259,6 +259,15 @@ This will install a Chrome PWA and now all keybindings will work!
 
 For other browsers you'll have to remap keybindings unfortunately.
 
+## Why not use Microsoft's VS Code Remote extensions?
+
+Unfortunately, Microsoft has opted to make them closed source and
+it is against their TOS to use the published extensions with VSIX
+so we are unable to add them to our marketplace.
+
+We might reimplement them at some point.
+You can follow [#1315](https://github.com/cdr/code-server/issues/1315) for updates.
+
 ## Enterprise
 
 Visit [our enterprise page](https://coder.com) for more information about our