Port modern github light theme

[mkslanc]

Issue #, if available: #5589

Description of changes:

• I couldn't locate the source of the original GitHub theme, so I have not altered it to avoid disrupting the user experience for those accustomed to it. I have marked it as legacy for clarity.
• This update is a port of the official GitHub theme from VS Code. The port was inspired by the ace's tmTheme tool

The differences in colors are due to the usage of different tokens in the highlighting modes.

P.S.: If this proves valuable, I could also port the remaining dark and high contrast themes.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Pull Request Checklist:

• No backwards incompatible changes were made to Ace's public interface which is defined through the main typings file (ace.d.ts) and its references:
  • https://github.com/ajaxorg/ace/blob/master/ace.d.ts
  • https://github.com/ajaxorg/ace/blob/master/ace-modes.d.ts
  • https://github.com/ajaxorg/ace/blob/master/ace-extensions.d.ts

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.79%. Comparing base (16c95b3) to head (2ed24ca).
Report is 1 commits behind head on master.

❗ Current head 2ed24ca differs from pull request most recent head 9e9a9ac

Please upload reports for the commit 9e9a9ac to get more accurate results.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5597   +/-   ##
=======================================
  Coverage   86.79%   86.79%           
=======================================
  Files         594      594           
  Lines       43091    43091           
  Branches     7147     7147           
=======================================
  Hits        37400    37400           
  Misses       5691     5691           

Flag	Coverage Δ
unittests	86.79% <ø> (ø)

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[akoreman]

Hi, I think the new theme looks pretty good! Not fully sure whether the classic in the theme name conveys that this is the most modern one people should use if they want to have a GH-like theme? Maybe GitHub Default could work (mirroring how they're called in the VSC extension)? This could also help to make it more clear which theme is which if we want to add the high-contrast theme variants in future as well.

[mkslanc]

Hi, I think the new theme looks pretty good! Not fully sure whether the classic in the theme name conveys that this is the most modern one people should use if they want to have a GH-like theme? Maybe GitHub Default could work (mirroring how they're called in the VSC extension)? This could also help to make it more clear which theme is which if we want to add the high-contrast theme variants in future as well.

Hey, I agree. + I added few missed token scopes for html/xml

[dbitouze]

I can't wait to see this theme integrated into Ace! 😊