What are documentation comments in Xcode?

Xcode 5 now has built-in support for DOxygen style comments. So, you can comment your methods like this:

/*!
 * Provides an NSManagedObjectContext singleton appropriate for use on the main 
 * thread. If the context doesn't already exist it is created and bound to the 
 * persistent store coordinator for the application, otherwise the existing 
 * singleton contextis returned.
 * \param someParameter You can even add parameters
 * \returns The a shared NSManagedObjectContext for the application.
 */
+ (NSManagedObjectContext *)sharedContext;

Inline help will look like this:

Quick help will look like this:

And sidebar help will look like this:

Here's a handy code snippet you can add the your Xcode Code Snippet library to make method documentation simple:

/**
 <#description#>
 @param <#parameter#>
 @returns <#retval#>
 @exception <#throws#>
 */

Now, you can just type "doxy" and poof! You have your doxygen template.