fix(linter/no-unused-vars): mark the class/function in the new expression as used (#5306)

Fix: #5274

Author: magic-akari

crates/oxc_linter/src/rules/eslint/no_unused_vars/allowed.rs

@@ -42,6 +42,9 @@ impl<'s, 'a> Symbol<'s, 'a> {
                 // e.g. var foo = function bar() { }
                 // we don't want to check for violations on `bar`, just `foo`
                 | AstKind::VariableDeclarator(_)
+                // new (class CustomRenderer{})
+                // new (function() {})
+                | AstKind::NewExpression(_)
                 => {
                     return true;
                 }

crates/oxc_linter/src/rules/eslint/no_unused_vars/tests/oxc.rs

@@ -13,6 +13,12 @@ fn test_vars_simple() {
         ("let a = 1; if (true) { console.log(a) }", None),
         ("let _a = 1", Some(json!([{ "varsIgnorePattern": "^_" }]))),
         ("const { foo: _foo, baz } = obj; f(baz);", Some(json!([{ "varsIgnorePattern": "^_" }]))),
+        (
+            r"export const rendered = marked(markdown, {
+                  renderer: new (class CustomRenderer extends Renderer {})(),
+              });",
+            None,
+        ),
     ];
     let fail = vec![
         ("let a = 1", None),