fix(e2e-guide): conform code block styling to code-line convention

Author: myoshi2891

app/e2e-testing-guide.css

@@ -644,10 +644,15 @@
 .page-e2e .code-pre-div {
     padding: 1.25rem 1.5rem;
     overflow-x: auto;
-    white-space: pre;
     font-family: var(--font-mono);
     font-size: 12.5px;
     line-height: 1.7;
     color: #c9d1e0;
     display: block;
 }
+
+.page-e2e .code-line {
+    display: block;
+    white-space: pre;
+}
+

next-env.d.ts

@@ -1,6 +1,6 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/dev/types/routes.d.ts";
+import "./.next/types/routes.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.