Feat: Add scroll diff decorators

[mkslanc]

Issue #, if available:

Description of changes:

• Improve placement of error decorators (now they would better reflect folds/wraps and lineWidgets)
• Add diff decorators for both inline/split diff views
  
  

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

Attention: Patch coverage is 96.95652% with 7 lines in your changes missing coverage. Please review.

Project coverage is 87.67%. Comparing base (35e1be5) to head (04f0b50).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/ext/diff/base_diff_view.js	94.54%	3 Missing ⚠️
src/layer/decorators.js	95.91%	2 Missing ⚠️
src/ext/diff/diff_test.js	98.11%	1 Missing ⚠️
src/ext/diff/scroll_diff_decorator.js	98.52%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5807      +/-   ##
==========================================
+ Coverage   87.61%   87.67%   +0.05%     
==========================================
  Files         613      614       +1     
  Lines       45774    45940     +166     
  Branches     7507     7529      +22     
==========================================
+ Hits        40106    40276     +170     
+ Misses       5668     5664       -4     

Flag	Coverage Δ
unittests	87.67% <96.95%> (+0.05%)	⬆️

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[akoreman]

The decorator for diffs looks really cool 🚀 @mkslanc could you please resolve the merge conflicts for this PR

[mkslanc]

The decorator for diffs looks really cool 🚀 @mkslanc could you please resolve the merge conflicts for this PR

This should make it.