Styles: Less file housecleaning

[jeremywiebe]

A round of Less file cleanup. There were a bunch of unused variables and files. I figured out what was unused by running yarn build --watch and then starting to delete variables. Any time there was a varaible that was still in use, there would be an error like this [!] (plugin commonjs--resolver) Error: variable @gray95 is undefined.

• Get rid of variables.shared.less and move the single used variable to variables.less
• Rename articles.less to styles.less as it has rules for both articles and exercises!
• Remove completely unused variables.bootstrap.less
• Remove outdated comment
• Extract zoom styles to own file out of styles.less
• Trim out more unused variables from variables.less

Issue: --none--

Test plan:

yarn build is successful (our builds process Less files into CSS and so if there's variable references that no longer exist, it will fail)

[github-actions]

Size Change: -3 B (0%)

Total Size: 834 kB

Filename	Size	Change
packages/perseus/dist/es/index.js	403 kB	-3 B (0%)

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	38.1 kB
packages/kmath/dist/es/index.js	4.25 kB
packages/math-input/dist/es/index.js	79 kB
packages/perseus-core/dist/es/index.js	908 B
packages/perseus-editor/dist/es/index.js	270 kB
packages/perseus-error/dist/es/index.js	877 B
packages/perseus-linter/dist/es/index.js	21.8 kB
packages/pure-markdown/dist/es/index.js	3.77 kB
packages/simple-markdown/dist/es/index.js	12.4 kB

_{compressed-size-action}

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (d9b74a3) 59.43% compared to head (42e9bc9) 60.72%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #877      +/-   ##
==========================================
+ Coverage   59.43%   60.72%   +1.28%     
==========================================
  Files         417      419       +2     
  Lines       99579    99596      +17     
  Branches     6053     8607    +2554     
==========================================
+ Hits        59187    60478    +1291     
+ Misses      40392    39118    -1274     

Files	Coverage Δ
packages/perseus/src/renderer.tsx	92.56% <100.00%> (ø)
packages/perseus/src/styles/shared.ts	100.00% <100.00%> (ø)
packages/perseus/src/util/sizing-utils.ts	69.56% <100.00%> (ø)
packages/perseus/src/widgets/explanation.tsx	94.63% <100.00%> (ø)

... and 71 files with indirect coverage changes

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[jeremywiebe]

This chunk of styles was moved to zoom.less

[khan-actions-bot]

Gerald

Required Reviewers

• @Khan/perseus for changes to .changeset/grumpy-icons-retire.md, packages/perseus/src/renderer.tsx, packages/perseus/src/styles/perseus-renderer.less, packages/perseus/src/styles/shared.ts, packages/perseus/src/styles/styles.less, packages/perseus/src/styles/variables.less, packages/perseus/src/styles/zoom.less, packages/perseus/src/util/sizing-utils.ts, packages/perseus/src/widgets/explanation.tsx

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[nedredmond]

All looks good to me! Thanks, @jeremywiebe !