Added sswig.swift-lang (#721)

Author: hpux735

extensions.json

@@ -1308,6 +1308,9 @@
   "sorbet.sorbet-vscode-extension": {
     "repository": "https://github.com/sorbet/sorbet"
   },
+  "sswg.swift-lang": {
+    "repository": "https://github.com/swift-server/vscode-swift"
+  },
   "steoates.autoimport": {
     "repository": "https://github.com/soates/Auto-Import"
   },