Remove the heuristic where long selector lists wouldn't be trimmed

Testing this against the `@extend`-heavy stylesheets in
vinceliuice/Colloid-gtk-theme, trimming everywhere actually *improves*
performance rather than reducing it.

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.77.3
+
+* Fully trim redundant selectors generated by `@extend`.
+
 ## 1.77.2
 
 * Don't emit deprecation warnings for functions and mixins beginning with `__`.

lib/src/extend/extension_store.dart

@@ -901,13 +901,6 @@ class ExtensionStore {
   // document, and thus should never be trimmed.
   List<ComplexSelector> _trim(List<ComplexSelector> selectors,
       bool isOriginal(ComplexSelector complex)) {
-    // Avoid truly horrific quadratic behavior.
-    //
-    // TODO(nweiz): I think there may be a way to get perfect trimming without
-    // going quadratic by building some sort of trie-like data structure that
-    // can be used to look up superselectors.
-    if (selectors.length > 100) return selectors;
-
     // This is n² on the sequences, but only comparing between separate
     // sequences should limit the quadratic behavior. We iterate from last to
     // first and reverse the result so that, if two selectors are identical, we

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.77.2
+version: 1.77.3
 description: A Sass implementation in Dart.
 homepage: https://github.com/sass/dart-sass