Update description of Code

Author: arobase-che

readme.md

@@ -157,14 +157,16 @@ Yields:
 ### `Code`
 
 `Code` ([`Text`][text]) occurs at block level (see
-[`InlineCode`][inlinecode] for code spans).  `Code` sports a language
-tag (when using GitHub Flavoured Markdown fences with a flag, `null`
-otherwise).
+[`InlineCode`][inlinecode] for code spans).  `Code` supports an
+info string and a language tag (when the line with the opening fence
+contains some text, it is stored as the info string, the first word
+of the info string is stored as the language tag, null otherwise)
 
 ```idl
 interface Code <: Text {
   type: "code";
   lang: string | null;
+  infoString: string | null;
 }
 ```
 
@@ -180,6 +182,7 @@ Yields:
 {
   "type": "code",
   "lang": null,
+  "infoString": null,
   "value": "foo()"
 }
 ```