test: adopt Playwright test()/test.describe() naming in e2e specs

Mechanical rename of it() -> test() and describe() -> test.describe() so the
subsequent Playwright migration diff only touches test bodies, not the
suite/case wrappers.

e2e/i18n.spec.ts

@@ -1,29 +1,29 @@
 import { MaputnikDriver } from "./maputnik-driver";
 
-describe("i18n", () => {
+test.describe("i18n", () => {
   const { beforeAndAfter, get, when, then } = new MaputnikDriver();
   beforeAndAfter();
 
-  describe("language detector", () => {
-    it("English", () => {
+  test.describe("language detector", () => {
+    test("English", () => {
       const url = "?lng=en";
       when.visit(url);
       then(get.elementByTestId("maputnik-lang-select")).shouldHaveValue("en");
     });
 
-    it("Japanese", () => {
+    test("Japanese", () => {
       const url = "?lng=ja";
       when.visit(url);
       then(get.elementByTestId("maputnik-lang-select")).shouldHaveValue("ja");
     });
   });
 
-  describe("language switcher", () => {
+  test.describe("language switcher", () => {
     beforeEach(() => {
       when.setStyle("layer");
     });
 
-    it("the language switcher switches to Japanese", () => {
+    test("the language switcher switches to Japanese", () => {
       const selector = "maputnik-lang-select";
       then(get.elementByTestId(selector)).shouldExist();
       when.select(selector, "ja");