Add linux limitations badge to schemes api

Author: SerafimArts

Writerside/topics/webview/schemes-api.md

@@ -10,6 +10,7 @@ programmatically, without actual requests to the server (without network).
 
 ## Registration
 <secondary-label ref="macos-limitations"/>
+<secondary-label ref="linux-limitations"/>
 
 To enable processing of specific protocols, you should specify
 them in the list of schemes.