ARIA1 Fix typos and indentation issues

This pull request includes typo and indentation issues.

- Removed trailing spaces
- Fixed typos
  - s/&lt;html lang="en-us"">/&lt;html lang="en-us">/
   - s/application:xhtml+xml/application\/xhtml+xml/
- Fixed XHTML 1.1 + ARIA DOCTYPE in example 5 as per http://www.w3.org/TR/2014/REC-wai-aria-20140320/appendices#xhtml_dtd
- Fixed indentation of examples