add a separate scope to URL protocol and www

[eugenesvk]

I wanted to deemphasize protocol highlighting in links (http) as well as the usually optional www., so added separate scopes to them

Syntax tests failed locally before my edits, and the number of failed tests didn't change

(btw, got confused by https://github.com/SublimeText-Markdown/MarkdownEditing/blob/master/CONTRIBUTING.md again, if there are no milestones, would you please update the doc to reflect whatever actual scheme you're maintaining in this repo?)

[codecov-commenter]

:warning: Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Please upload report for BASE (master@8bd9216). Learn more about missing BASE report.

:exclamation: Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #732   +/-   ##
=========================================
  Coverage          ?   36.07%           
=========================================
  Files             ?        7           
  Lines             ?     1095           
  Branches          ?        0           
=========================================
  Hits              ?      395           
  Misses            ?      700           
  Partials          ?        0           

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.