Add linter to check Expression button sets

[handeyeco]

Summary:

Checks Expression answers to see if they require a symbol that's not available to the keypad.

Issue: LEMS-2199

Test plan:

• Make an Expression widget in the content editor
• Add \\sqrt to an answer
• Make sure the "prealgebra" button set is not enabled
• You should see a warning that you need to enable "prealgebra"

[khan-actions-bot]

Gerald

Required Reviewers

• @Khan/perseus for changes to .changeset/fluffy-otters-join.md, packages/perseus-linter/src/__tests__/rules.test.ts, packages/perseus-linter/src/rules/all-rules.ts, packages/perseus-linter/src/rules/expression-widget.ts

---

Don't want to be involved in this pull request? Comment #removeme and we won't notify you of further changes.

[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (9a62e3f) and published it to npm. You
can install it using the tag PR1531.

Example:

yarn add @khanacademy/perseus@PR1531

If you are working in Khan Academy's webapp, you can run:

./dev/tools/bump_perseus_version.sh -t PR1531

[github-actions]

Size Change: +409 B (+0.05%)

Total Size: 854 kB

Filename	Size	Change
packages/perseus-linter/dist/es/index.js	22.1 kB	+409 B (+1.89%)

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	38.3 kB
packages/kmath/dist/es/index.js	4.27 kB
packages/math-input/dist/es/index.js	80.8 kB
packages/math-input/dist/es/strings.js	1.73 kB
packages/perseus-core/dist/es/index.js	1.48 kB
packages/perseus-editor/dist/es/index.js	273 kB
packages/perseus/dist/es/index.js	413 kB
packages/perseus/dist/es/strings.js	3.29 kB
packages/pure-markdown/dist/es/index.js	3.67 kB
packages/simple-markdown/dist/es/index.js	12.4 kB

_{compressed-size-action}

[codecov]

Codecov Report

Attention: Patch coverage is 96.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 70.59%. Comparing base (3044038) to head (9a62e3f).
Report is 40 commits behind head on LEMS-2199/prework.

Files	Patch %	Lines
...ages/perseus-linter/src/rules/expression-widget.ts	95.83%	2 Missing ⚠️

Additional details and impacted files

@@                  Coverage Diff                  @@
##           LEMS-2199/prework    #1531      +/-   ##
=====================================================
- Coverage              71.75%   70.59%   -1.16%     
=====================================================
  Files                    520      514       -6     
  Lines                 106610   105759     -851     
  Branches               11948    11458     -490     
=====================================================
- Hits                   76495    74665    -1830     
- Misses                 30115    31094     +979     

Files	Coverage Δ
packages/perseus-linter/src/rules/all-rules.ts	100.00% <100.00%> (ø)
...ages/perseus-linter/src/rules/expression-widget.ts	95.83% <95.83%> (ø)

... and 83 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3044038...9a62e3f. Read the comment docs.