fix: improve types for .has_next, .next_sibling and .first_child

[bartveneman]

No description provided.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.49%. Comparing base (7078ab0) to head (f60b98f).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #209   +/-   ##
=======================================
  Coverage   93.49%   93.49%           
=======================================
  Files          17       17           
  Lines        2938     2938           
  Branches      809      809           
=======================================
  Hits         2747     2747           
  Misses        191      191           

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[codecov-commenter]

Bundle Report

Changes will decrease total bundle size by 448 bytes (-0.25%) ⬇️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
@projectwallace/css-parser-esm	180.86kB	-448 bytes (-0.25%) ⬇️

Affected Assets, Files, and Routes:

view changes for bundle: @projectwallace/css-parser-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
node-types-DXNwTg3_.d.ts (New)	22.04kB	22.04kB	100.0% 🚀
node-types-DENZmlh1.d.ts (Deleted)	-22.48kB	0 bytes	-100.0% 🗑️