fix(#31): var naming, search api doc

[h1alexbel]

ref #31

---

PR-Codex overview

The focus of this PR is to update URLs in the README file and improve function parameter naming and result handling in index.js.

Detailed summary

• Updated GitHub Search API query URL in README
• Improved parameter naming in resultsInDateRange function
• Enhanced result handling in resultsInDateRange function
• Handled potential null value in writeFiles function

✨ Ask PR-Codex anything about this PR by commenting with /codex {your question}

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 9.81%. Comparing base (286d4ca) to head (77c20e2).
Report is 10 commits behind head on master.

Files	Patch %	Lines
src/index.js	0.00%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           master     #32      +/-   ##
=========================================
- Coverage    9.87%   9.81%   -0.07%     
=========================================
  Files           9       9              
  Lines         162     163       +1     
  Branches       24      25       +1     
=========================================
  Hits           16      16              
- Misses        146     147       +1     

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