fix: add page title to ad page, resolves #17

[RNR1]

PR Checklist

• [x] Addresses an existing open issue: fixes #17
• [x] That issue was marked as status: accepting prs
• [x] Steps in CONTRIBUTING.md were taken

Overview

I added a valid HTML page title to the "Ad" page. When the "month" or "year" search params are missing or invalid, the page title will be "Ad | Philly JS Club," otherwise, it will display "Ad (${month} ${year}), same as it will display in the UI.

[JoshuaKGoldberg]

@allcontributors add @RNR1 for code