Slice: padding

[donutloop]

• LeftPadding adds padding to the left begin of a slice.
• RightPadding adds padding to the right end of a slice.

[donutloop]

@duke-git Please review

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 76.47059% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 80.57%. Comparing base (73c97af) to head (164f0fa).

Files	Patch %	Lines
slice/slice.go	76.47%	2 Missing and 2 partials ⚠️

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

Additional details and impacted files

@@            Coverage Diff             @@
##               rc     #201      +/-   ##
==========================================
- Coverage   80.58%   80.57%   -0.01%     
==========================================
  Files          65       65              
  Lines        7545     7562      +17     
==========================================
+ Hits         6080     6093      +13     
- Misses       1093     1095       +2     
- Partials      372      374       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.