docs: update readme

Author: azu

README.md

@@ -2,6 +2,19 @@
 
 Paste or drop code into the editor and inspect the generated AST.
 
+## Fork version for textlint
+
+This version limited for [textlint](http://textlint.github.io/ "textlint").
+
+- Markdown
+- Txt
+
+Bellow is original text.
+
+Please Visit [https://textlint.github.com/astexplorer](https://textlint.github.com/astexplorer).
+
+-----
+
 The AST explorer provides following code parsers:
 
 - JavaScript: