Doc: Replace "@property @type {Type}" with "@property {Type}".

Also removed a few redundant headings in class documentation
comments. There is already an @class and it looks a bit odd  in
the generated pages:
 <h2>TextString</h2>
 <p>TextString</p>
 <p>This class provides a ...</p>

Change-Id: Ie311c6993ed02e79272dbde71f6a1bc252ef3037