Update the Blog post on Progressive Web Maps

[Malvoz]

The blog post is in need of some updates, to fix:

• Should be upgraded to use web-map.js (fixed in Get rid of old example. Refactor blog mapml into XHTML namespace. #525.)
• <map> shouldn't use the hidden attribute.
• Probably throw in a note about the accessibility issue of the <map is="web-map"> built-in that is present in some browsers (Chrome at least), otherwise uninformed developers might just use it without considering that users relying on their screen reader wont be able to user their maps.
• Regarding:
  
  

  Comments: 0

  The link is broken, it should point to https://discourse.wicg.io/t/progressive-web-maps/1730. And there are more than 0 comments.