Merge from vscode 81d7885dc2e9dc617e1522697a2966bc4025a45d (#5949)

* Merge from vscode 81d7885dc2e9dc617e1522697a2966bc4025a45d

* Fix vs unit tests and hygiene issue

* Fix strict null check issue

extensions/markdown-language-features/package.json

@@ -5,6 +5,7 @@
 	"version": "1.0.0",
 	"icon": "icon.png",
 	"publisher": "vscode",
+	"license": "MIT",
 	"aiKey": "AIF-d9b70cd4-b9f9-4d70-929b-a071c400b217",
 	"engines": {
 		"vscode": "^1.20.0"
@@ -313,7 +314,7 @@
 		"build-preview": "webpack --mode development"
 	},
 	"dependencies": {
-		"highlight.js": "9.13.1",
+		"highlight.js": "9.15.8",
 		"markdown-it": "^8.4.2",
 		"markdown-it-front-matter": "^0.1.2",
 		"vscode-extension-telemetry": "0.1.1",
@@ -323,7 +324,7 @@
 		"@types/highlight.js": "9.12.3",
 		"@types/lodash.throttle": "^4.1.3",
 		"@types/markdown-it": "0.0.2",
-		"@types/node": "^10.12.21",
+		"@types/node": "^10.14.8",
 		"lodash.throttle": "^4.1.1",
 		"mocha-junit-reporter": "^1.17.0",
 		"mocha-multi-reporters": "^1.1.7",