The link is intentionally just a placeholder
If you only have one URL, then quoting it as str might be easier.
#"https://example.com"
You could test it with HTML export:
$ echo 'https://example.com' | typst compile - - --format html --features html
<!DOCTYPE html>
<html>
<head>…</head>
<body>
<p><a href="https://example.com">https://example.com</a></p>
</body>
</html>
$ echo '#"https://example.com"' | typst compile - - --format html --features html
<!DOCTYPE html>
<html>
<head>…</head>
<body>
<p>https://example.com</p>
</body>
</html>