perf: implement fast path for declarations w/o hack or prefix

[bartveneman]

before

after

[codecov-commenter]

Codecov Report

❌ Patch coverage is 91.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.96%. Comparing base (c1cc139) to head (b14f496).

Files with missing lines	Patch %	Lines
src/parse-declaration.ts	91.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #167      +/-   ##
==========================================
- Coverage   94.96%   94.96%   -0.01%     
==========================================
  Files          16       16              
  Lines        2880     2877       -3     
  Branches      805      804       -1     
==========================================
- Hits         2735     2732       -3     
  Misses        145      145              

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[codecov-commenter]

Bundle Report

Changes will decrease total bundle size by 3 bytes (-0.0%) ⬇️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
@projectwallace/css-parser-esm	159.07kB	-3 bytes (-0.0%) ⬇️

Affected Assets, Files, and Routes:

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

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
parse-declaration.js	-3 bytes	6.01kB	-0.05%

Files in parse-declaration.js:

• ./src/parse-declaration.ts → Total Size: 5.65kB