fix error for Node.toString() (#24)

Author: gucong3000

package.json

@@ -1,6 +1,6 @@
 {
   "name": "postcss-syntax",
-  "version": "0.26.1",
+  "version": "0.27.0",
   "description": "Automatically switch PostCSS syntax by file extensions",
   "repository": {
     "type": "git",
@@ -37,12 +37,12 @@
     "chai": "^4.1.2",
     "codecov": "^3.0.2",
     "mocha": "^5.2.0",
-    "nyc": "^11.8.0",
+    "nyc": "^12.0.2",
     "postcss": "^6.0.22",
-    "postcss-html": ">=0.26.0",
-    "postcss-jsx": ">=0.26.0",
-    "postcss-less": "^1.1.5",
-    "postcss-markdown": ">=0.26.0",
+    "postcss-html": ">=0.27.0",
+    "postcss-jsx": ">=0.27.0",
+    "postcss-less": "^2.0.0",
+    "postcss-markdown": ">=0.27.0",
     "postcss-safe-parser": "^3.0.1",
     "postcss-scss": "^1.0.5",
     "sugarss": "^1.0.1"

patch-postcss.js

@@ -44,6 +44,7 @@ function patch (Document) {
 	let fn;
 	let file;
 	if (Document) {
+		patch();
 		fn = patchDocument.bind(this, Document);
 		file = "lazy-result";
 	} else {