feat: support arrow functions

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes 🚀 Feature: Support arrow functions too  #2
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

Removes the now-outdated assumption that functions always have a body with statements.

[codecov]

Codecov Report

Attention: Patch coverage is 93.61702% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 85.55%. Comparing base (6cea659) to head (5260f51).
Report is 1 commits behind head on main.

❗ Current head 5260f51 differs from pull request most recent head ffb71ac

Please upload reports for the commit ffb71ac to get more accurate results.

Files	Patch %	Lines
src/isSmallFunctionLike.ts	78.57%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #181      +/-   ##
==========================================
+ Coverage   83.40%   85.55%   +2.15%     
==========================================
  Files           7        8       +1     
  Lines         235      270      +35     
  Branches       37       46       +9     
==========================================
+ Hits          196      231      +35     
  Misses         39       39              

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[github-actions]

🎉 This is included in version v0.2.0 🎉

The release is available on:

• GitHub releases
• npm package (@latest dist-tag)

Cheers! 📦🚀