Documentation for "not_allowed" value in "incognito" manifest field.

chrome/common/extensions/docs/templates/json/manifest.json

 {
   "app": {
     "documentation": "manifest/app",
     "example": {},
     "level": "required"
   },
   "app.background": {
     "example": {"scripts": ["background.js"]},
     "level": "required"
   },
@@ skipping 97 matching lines @@
     "documentation": "manifest/icons",
     "example": {},
     "level": "recommended"
   },
   "import": {
     "documentation": "shared_modules",
     "example": [{"id": "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"}]
   },
   "incognito": {
     "documentation": "manifest/incognito",
-    "example": "spanning or split"
+    "example": "spanning, split, or not_allowed"
   },
   "key": {
     "documentation": "manifest/key",
     "example": "publicKey"
   },
   "kiosk_enabled": {
     "documentation": "manifest/kiosk_enabled#kiosk_enabled",
     "example": true
   },
   "kiosk_only": {
@@ skipping 114 matching lines @@
   },
   "web_accessible_resources": {
     "documentation": "manifest/web_accessible_resources",
     "example": []
   },
   "webview": {
     "documentation": "tags/webview#local_resources",
     "example": {}
   }
 }