Update AppleDoc install instructions
@tomaz tagged a new version of AppleDoc which resolves the issue requiring the `--HEAD` param to `brew`, and @adamv [pulled in the change](Homebrew/homebrew#14693) to mxcl/homebrew that both updates to the new code and also uses the [new compile-time template location](tomaz/appledoc#231) to avoid the second step.
|@@ -33,8 +33,7 @@ $ [sudo] gem install cocoapods|
|33||33||If you want to have CocoaPods generate documentation for each library, then install the [appledoc](http://gentlebytes.com/appledoc/) tool:|
|36||-$ brew install appledoc --HEAD|
|37||-$ ln -sf "`brew --prefix`/Cellar/appledoc/HEAD/Templates" ~/Library/Application\ Support/appledoc|
|36||+$ brew install appledoc|
|40||39||Now that you've got CocoaPods installed you can easily add it to your project.|