Form an MD link from highlighted text and URL

PopClip Extensions
2

This should do it:

// #popclip
// name: GH Issue
// language: javascript
const text = popclip.input.text;
const url = `https://github.com/repo/issue/${encodeURIComponent(text)}`;
const md = `[${text}](${url})`;
popclip.copyText(md);

(The above block is an extension snippet — select it then click “Install Extension” in PopClip.)