vscode: Remove electron dependency but keep types

Electron doesn't support FreeBSD.

Author: nhooyr

lib/vscode/package.json

@@ -116,7 +116,6 @@
     "css-loader": "^3.2.0",
     "debounce": "^1.0.0",
     "deemon": "^1.4.0",
-    "electron": "9.3.3",
     "eslint": "6.8.0",
     "eslint-plugin-jsdoc": "^19.1.0",
     "eslint-plugin-mocha": "8.0.0",