feat: support auto complete for http header names

[GalacticHypernova]

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

NOTE: I marked it as a new feature as technically there wasn't any autocompletion beforehand. If I should change this to enhancement please do let me know and I apologize in advance.

📚 Description

This PR adds HTTP header autocompletion for better DX. Tested on my local machine, this makes writing headers more convenient for many header manipulation operations.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[codecov]

Codecov Report

Merging #542 (2afa8d8) into main (9e81e4e) will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #542      +/-   ##
==========================================
+ Coverage   83.74%   83.83%   +0.08%     
==========================================
  Files          31       31              
  Lines        3544     3563      +19     
  Branches      543      540       -3     
==========================================
+ Hits         2968     2987      +19     
  Misses        576      576              

Files	Coverage Δ
src/types.ts	100.00% <100.00%> (ø)
src/utils/request.ts	92.89% <100.00%> (+0.18%)	⬆️
src/utils/response.ts	78.90% <100.00%> (+0.23%)	⬆️

[pi0]

This is a nice addition thanks!

[GalacticHypernova]

Always glad to help!
And thanks for teaching me to put such things in src/types, will remember to do so in future PR's!