Auto merge of #19589 - tigercosmos:e1, r=emilio
Auto merge of #19589 - tigercosmos:e1, r=emilio

remove unused `Auto` in test of serialization

<!-- Please describe your changes on the following line: -->
```
warning: unused import: `Auto`
 --> /Users/tigercosmos/servo/tests/unit/style/properties/serialization.rs:9:40
  |
9 | use style::values::{CustomIdent, RGBA, Auto};
  |                                        ^^^^
  |
  = note: #[warn(unused_imports)] on by default
```

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jimberlage/servo,jimberlage/servo,emilio/servo,larsbergstrom/servo,larsbergstrom/servo,sadmansk/servo,sadmansk/servo,splav/servo,peterjoel/servo,anthgur/servo,emilio/servo,szeged/servo,thiagopnts/servo,mbrubeck/servo,dati91/servo,notriddle/servo,emilio/servo,anthgur/servo,peterjoel/servo,upsuper/servo,pyfisch/servo,avadacatavra/servo,ConnorGBrewster/servo,nnethercote/servo,dati91/servo,saneyuki/servo,paulrouget/servo,szeged/servo,szeged/servo,fiji-flo/servo,dati91/servo,emilio/servo,mattnenterprise/servo,splav/servo,splav/servo,notriddle/servo,jimberlage/servo,peterjoel/servo,notriddle/servo,paulrouget/servo,anthgur/servo,pyfisch/servo,pyfisch/servo,thiagopnts/servo,splav/servo,paulrouget/servo,saneyuki/servo,sadmansk/servo,upsuper/servo,paulrouget/servo,saneyuki/servo,dati91/servo,saneyuki/servo,fiji-flo/servo,dati91/servo,mattnenterprise/servo,jimberlage/servo,upsuper/servo,SimonSapin/servo,emilio/servo,mbrubeck/servo,larsbergstrom/servo,ConnorGBrewster/servo,cbrewster/servo,SimonSapin/servo,SimonSapin/servo,cbrewster/servo,peterjoel/servo,ConnorGBrewster/servo,pyfisch/servo,ConnorGBrewster/servo,fiji-flo/servo,KiChjang/servo,anthgur/servo,jimberlage/servo,mattnenterprise/servo,dati91/servo,szeged/servo,mattnenterprise/servo,paulrouget/servo,pyfisch/servo,fiji-flo/servo,fiji-flo/servo,KiChjang/servo,ConnorGBrewster/servo,nnethercote/servo,thiagopnts/servo,DominoTree/servo,sadmansk/servo,saneyuki/servo,canaltinova/servo,larsbergstrom/servo,mbrubeck/servo,thiagopnts/servo,DominoTree/servo,larsbergstrom/servo,KiChjang/servo,fiji-flo/servo,avadacatavra/servo,peterjoel/servo,ConnorGBrewster/servo,avadacatavra/servo,paulrouget/servo,jimberlage/servo,nnethercote/servo,KiChjang/servo,canaltinova/servo,mbrubeck/servo,splav/servo,avadacatavra/servo,szeged/servo,KiChjang/servo,peterjoel/servo,upsuper/servo,larsbergstrom/servo,splav/servo,canaltinova/servo,canaltinova/servo,saneyuki/servo,sadmansk/servo,KiChjang/servo,sadmansk/servo,larsbergstrom/servo,KiChjang/servo,DominoTree/servo,szeged/servo,saneyuki/servo,upsuper/servo,notriddle/servo,saneyuki/servo,paulrouget/servo,canaltinova/servo,thiagopnts/servo,splav/servo,dati91/servo,KiChjang/servo,pyfisch/servo,notriddle/servo,sadmansk/servo,anthgur/servo,pyfisch/servo,nnethercote/servo,nnethercote/servo,mattnenterprise/servo,szeged/servo,splav/servo,upsuper/servo,thiagopnts/servo,emilio/servo,larsbergstrom/servo,larsbergstrom/servo,paulrouget/servo,cbrewster/servo,DominoTree/servo,ConnorGBrewster/servo,peterjoel/servo,mbrubeck/servo,jimberlage/servo,notriddle/servo,nnethercote/servo,avadacatavra/servo,notriddle/servo,splav/servo,avadacatavra/servo,avadacatavra/servo,paulrouget/servo,emilio/servo,mbrubeck/servo,DominoTree/servo,nnethercote/servo,fiji-flo/servo,thiagopnts/servo,thiagopnts/servo,upsuper/servo,szeged/servo,pyfisch/servo,SimonSapin/servo,mbrubeck/servo,emilio/servo,pyfisch/servo,mattnenterprise/servo,peterjoel/servo,jimberlage/servo,anthgur/servo,cbrewster/servo,notriddle/servo,larsbergstrom/servo,peterjoel/servo,SimonSapin/servo,fiji-flo/servo,notriddle/servo,anthgur/servo,szeged/servo,DominoTree/servo,mattnenterprise/servo,peterjoel/servo,SimonSapin/servo,emilio/servo,ConnorGBrewster/servo,cbrewster/servo,cbrewster/servo,KiChjang/servo,szeged/servo,nnethercote/servo,splav/servo,canaltinova/servo,DominoTree/servo,canaltinova/servo,upsuper/servo,dati91/servo,emilio/servo,cbrewster/servo,cbrewster/servo,nnethercote/servo,SimonSapin/servo,DominoTree/servo,SimonSapin/servo,saneyuki/servo,avadacatavra/servo,anthgur/servo,mattnenterprise/servo,canaltinova/servo,DominoTree/servo,sadmansk/servo,nnethercote/servo,jimberlage/servo,KiChjang/servo,paulrouget/servo,pyfisch/servo,saneyuki/servo,notriddle/servo,mbrubeck/servo,DominoTree/servo