doc: add `added:` information for punycode

PR-URL: https://github.com/nodejs/node/pull/6805
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/punycode.md

@@ -2,11 +2,14 @@
 
     Stability: 2 - Stable
 
-[Punycode.js][] is bundled with Node.js v0.6.2+. Use `require('punycode')` to
+[Punycode.js][] is bundled with Node.js v0.5.1+. Use `require('punycode')` to
 access it. (To use it with other Node.js versions, use npm to install the
 `punycode` module first.)
 
 ## punycode.decode(string)
+<!-- YAML
+added: v0.5.1
+-->
 
 Converts a Punycode string of ASCII-only symbols to a string of Unicode symbols.
 
@@ -17,6 +20,9 @@ punycode.decode('--dqo34k'); // '☃-⌘'
 ```
 
 ## punycode.encode(string)
+<!-- YAML
+added: v0.5.1
+-->
 
 Converts a string of Unicode symbols to a Punycode string of ASCII-only symbols.
 
@@ -27,6 +33,9 @@ punycode.encode('☃-⌘'); // '--dqo34k'
 ```
 
 ## punycode.toASCII(domain)
+<!-- YAML
+added: v0.6.1
+-->
 
 Converts a Unicode string representing a domain name to Punycode. Only the
 non-ASCII parts of the domain name will be converted, i.e. it doesn't matter if
@@ -39,6 +48,9 @@ punycode.toASCII('☃-⌘.com'); // 'xn----dqo34k.com'
 ```
 
 ## punycode.toUnicode(domain)
+<!-- YAML
+added: v0.6.1
+-->
 
 Converts a Punycode string representing a domain name to Unicode. Only the
 Punycoded parts of the domain name will be converted, i.e. it doesn't matter if
@@ -51,8 +63,14 @@ punycode.toUnicode('xn----dqo34k.com'); // '☃-⌘.com'
 ```
 
 ## punycode.ucs2
+<!-- YAML
+added: v0.7.0
+-->
 
 ### punycode.ucs2.decode(string)
+<!-- YAML
+added: v0.7.0
+-->
 
 Creates an array containing the numeric code point values of each Unicode
 symbol in the string. While [JavaScript uses UCS-2 internally][], this function
@@ -66,6 +84,9 @@ punycode.ucs2.decode('\uD834\uDF06'); // [0x1D306]
 ```
 
 ### punycode.ucs2.encode(codePoints)
+<!-- YAML
+added: v0.7.0
+-->
 
 Creates a string based on an array of numeric code point values.
 
@@ -75,6 +96,9 @@ punycode.ucs2.encode([0x1D306]); // '\uD834\uDF06'
 ```
 
 ## punycode.version
+<!-- YAML
+added: v0.6.1
+-->
 
 A string representing the current Punycode.js version number.