docs: document PR resource URI template and add corresponding test#668

Copilot wants to merge 2 commits intomaingithub/github-mcp-server:mainfrom

copilot/fix-a2b1f4f4-755c-4d7d-93e9-2f59d0a26a23github/github-mcp-server:copilot/fix-a2b1f4f4-755c-4d7d-93e9-2f59d0a26a23Copy head branch name to clipboard