use tsconfig.json#include for vscode.d.ts and vscode.proposed.d.ts, enables to remove most ref.d.ts-files

extensions/markdown-math/tsconfig.json

@@ -5,6 +5,7 @@
 		"types": []
 	},
 	"include": [
-		"src/**/*"
+		"src/**/*",
+		"../../src/vscode-dts/vscode.d.ts"
 	]
 }