Add support for boolean HTML attributes

[jugglinmike]

Currently, the following markup confuses CodeRay:

<textarea disabled>
  This text area has been disabled.
</textarea>

The file test1.xml hosted here has a good list of attributes that do not require a value, although there are new boolean attributes in the HTML5 spec:

• <iframe>: seamless and sandbox (source)
• <style>: scoped (source)

[korny]

Wow, that's awful - thank you for reporting! I'll fix it in the next release.

[korny]

v1.0.7.rc2 should have fixed this; can you test?

[korny]

I released this in 1.0.7. Hope it's fixed.

[jugglinmike]

8 months later, I'd like to confirm that this is, in fact, working on my end. Thanks!