Generates the +sharedInstance method in the class implementation section, for example, when calling the Code | Generate | +sharedInstance action.
The template is editable. Along with Objective-C expressions and comments, you can use predefined variables that will be then expanded into the corresponding values.
The predefined variables will take the following values:
${$CLASS_TYPE}   the name of the class where the method is implemented
All the predefined variables from the C File Header template (the Includes tab) are also available (${USER}, ${DATE}, etc.)