Fix a typo (#2329)

Author: Anushreebasics

pkgs/html/lib/src/query_selector.dart

@@ -178,20 +178,20 @@ class SelectorEvaluator extends Visitor {
     }
 
     // :before, :after, :first-letter/line can't match DOM elements.
-    if (_isLegacyPsuedoClass(node.name)) return false;
+    if (_isLegacyPseudoClass(node.name)) return false;
 
     throw _unimplemented(node);
   }
 
   @override
   bool visitPseudoElementSelector(PseudoElementSelector node) {
     // :before, :after, :first-letter/line can't match DOM elements.
-    if (_isLegacyPsuedoClass(node.name)) return false;
+    if (_isLegacyPseudoClass(node.name)) return false;
 
     throw _unimplemented(node);
   }
 
-  static bool _isLegacyPsuedoClass(String name) {
+  static bool _isLegacyPseudoClass(String name) {
     switch (name) {
       case 'before':
       case 'after':