fix private features' link in classes overview page (mdn#32206)

* fix private features' link in classes overview page

* Update files/en-us/web/javascript/reference/classes/index.md

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Co-authored-by: Joshua Chen <[email protected]>

files/en-us/web/javascript/reference/classes/index.md

@@ -179,7 +179,7 @@ class Rectangle {
 }
 ```
 
-Class fields are similar to object properties, not variables, so we don't use keywords such as `const` to declare them. In JavaScript, [private features](#private_class_features) use a special identifier syntax, so modifier keywords like `public` and `private` should not be used either.
+Class fields are similar to object properties, not variables, so we don't use keywords such as `const` to declare them. In JavaScript, [private features](#private_class_features_2) use a special identifier syntax, so modifier keywords like `public` and `private` should not be used either.
 
 As seen above, the fields can be declared with or without a default value. Fields without default values default to `undefined`. By declaring fields up-front, class definitions become more self-documenting, and the fields are always present, which help with optimizations.