fix: update documentation on configuring puppeteer (#9150)

This PR updates the docs regarding configuring puppeteer. In addition,
some changes have been made to the documentation generator to show
default values on the documentation site.

Also fixes: https://github.com/puppeteer/puppeteer/pull/9144

tools/generate_docs.ts

@@ -116,7 +116,10 @@ sidebar_position: 1
     generateDocs(inputs[0]!, outputs[0]!);
     spawnAndLog('prettier', '--ignore-path', 'none', '--write', 'docs');
   })
-    .inputs(['docs/puppeteer.api.json'])
+    .inputs([
+      'docs/puppeteer.api.json',
+      'tools/internal/custom_markdown_documenter.ts',
+    ])
     .outputs(['docs/api'])
     .build();
 })();