Issue #1592 Improve reporter documentation for mocha in browser.

You can pass the constructor function of your custom reporter in options and mocha will use it.

docs/index.md

@@ -1574,6 +1574,13 @@ mocha.setup({
 });
 ```
 
+Browser Mocha supports many, but not all [cli options](#command-line-usage).  
+To use a [cli option](#command-line-usage) that contains a "-", please convert the option to camel-case, (eg. `check-leaks` to `checkLeaks`).  
+Options that have additional/slightly different usage than the corresponding [cli option](#command-line-usage) are listed here:
+
+- reporter _{string|constructor}_
+  - Reporter name\*\* or custom reporter constructor. Available built in reporters that can be referenced by the name [found here](#reporters), and recommended reporters for the browser [here](#reporting).
+
 ### Browser-specific Option(s)
 
 The following option(s) _only_ function in a browser context:
@@ -1582,7 +1589,7 @@ The following option(s) _only_ function in a browser context:
 
 ### Reporting
 
-The "HTML" reporter is what you see when running Mocha in the browser. It looks like this:
+The "html" reporter is the default reporter when running Mocha in the browser. It looks like this:
 
 ![HTML test reporter](images/reporter-html.png?withoutEnlargement&resize=920,9999){:class="screenshot" lazyload="on"}
 

lib/mocha.js

@@ -83,7 +83,7 @@ exports.Test = require('./test');
  * @param {boolean} [options.inlineDiffs] - Display inline diffs?
  * @param {boolean} [options.invert] - Invert test filter matches?
  * @param {boolean} [options.noHighlighting] - Disable syntax highlighting?
- * @param {string} [options.reporter] - Reporter name.
+ * @param {string|constructor} [options.reporter] - Reporter name or constructor.
  * @param {Object} [options.reporterOption] - Reporter settings object.
  * @param {number} [options.retries] - Number of times to retry failed tests.
  * @param {number} [options.slow] - Slow threshold value.