[Call for Review] HTML page title is descriptive -- c4a8a4 -- Updates to web page definition and editorials

Hello all,

Ref:
https://github.com/act-rules/act-rules.github.io/pull/1912

This pr makes the following changes to the rule "HTML page title is descriptive":

* updates the definitions we are using
* proposes some editorial changes 
* addresses comments from previous round of review.

Call for review ends in one week.

Best.
--

Daniel Montalvo

Accessibility Education and Training Specialist W3C/WAI