fix: handle special Axios keywords when merging headers

[mrlubos]

Closes #1428

[stackblitz]

Run & review this pull request in StackBlitz Codeflow.

[changeset-bot]

🦋 Changeset detected

Latest commit: 458ef50

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@hey-api/client-axios	Patch
@example/openapi-ts-axios	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
hey-api-docs	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Dec 19, 2024 6:39pm

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.31%. Comparing base (680e55f) to head (458ef50).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1470   +/-   ##
=======================================
  Coverage   63.31%   63.31%           
=======================================
  Files         143      143           
  Lines       22332    22332           
  Branches     1848     1848           
=======================================
  Hits        14139    14139           
  Misses       8187     8187           
  Partials        6        6           

Flag	Coverage Δ
unittests	63.31% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

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

[pkg-pr-new]

Open in Stackblitz

npm i https://pkg.pr.new/@hey-api/client-axios@1470

npm i https://pkg.pr.new/@hey-api/openapi-ts@1470

npm i https://pkg.pr.new/@hey-api/client-fetch@1470

commit: 458ef50