Add visitor to add JavaDoc to a J.ClassDeclaration or J.MethodDeclaration

[traceyyoshima]

JavaDocs consist of Javadoc.Text and Javadoc.LineBreak and are not simple to create. The JavaTemplate may be used to generate correctly structured JavaDocs based on a String, and add the comment to a valid target.

[traceyyoshima]

Unassigning myself until the feature is requested. Auto-formatting does not work well on JavaDocs generated by the JavaTemplate and will take time to fix.