Refactor code-style

Author: wooorm

lib/handlers/index.js

@@ -37,8 +37,12 @@ exports.hr = require('./thematic-break');
 exports.pre = require('./code');
 exports.blockquote = require('./blockquote');
 
-exports.h1 = exports.h2 = exports.h3 =
-  exports.h4 = exports.h5 = exports.h6 = require('./heading');
+exports.h1 =
+exports.h2 =
+exports.h3 =
+exports.h4 =
+exports.h5 =
+exports.h6 = require('./heading');
 
 exports.a = require('./link');