fix: Show () for callbacks

* Show callback signatures

* Add output test for callback

* Reformat is_function

* Fix comparator

* Use camelCase #818

Author: davedoesdev

__tests__/fixture/simple-callback.input.js

@@ -0,0 +1,18 @@
+/**
+ * This takes a number and a callback and calls the callback with the number
+ * plus 3.
+ *
+ * @param {Number} n - The number.
+ * @param {simpleCallback} cb - The callback.
+ */
+function takesSimpleCallback(n, cb) {
+  cb(null, n + 3);
+}
+
+/**
+ * This callback takes an error and a number.
+ *
+ * @callback simpleCallback
+ * @param {?Error} err - The error.
+ * @param {Number} n - The number.
+ */

src/default_theme/index.js

@@ -9,6 +9,15 @@ var fs = require('fs'),
   LinkerStack = require('../').util.LinkerStack,
   hljs = require('highlight.js');
 
+function isFunction(section) {
+  return (
+    section.kind === 'function' ||
+    (section.kind === 'typedef' &&
+      section.type.type === 'NameExpression' &&
+      section.type.name === 'Function')
+  );
+}
+
 module.exports = function(
   comments: Array<Comment>,
   config: DocumentationConfig
@@ -34,7 +43,7 @@ module.exports = function(
         var prefix = '';
         if (section.kind === 'class') {
           prefix = 'new ';
-        } else if (section.kind !== 'function') {
+        } else if (!isFunction(section)) {
           return section.name;
         }
         return prefix + section.name + formatters.parameters(section, true);
@@ -44,7 +53,7 @@ module.exports = function(
         var prefix = '';
         if (section.kind === 'class') {
           prefix = 'new ';
-        } else if (section.kind !== 'function') {
+        } else if (!isFunction(section)) {
           return section.name;
         }
         if (section.returns.length) {