Package name not properly escaped in "Contents of package" link

The package's name inside the Contents of package link is not properly URL encoded

Steps to reproduce:

1. Go to a package page like https://pkgs.alpinelinux.org/package/edge/main/x86_64/libstdc++
2. Click the Contents of package link
3. URL contains &name=libstdc++, Package filter contains libstdc and there are no results
4. Manually search for libstdc++ on the same page
5. URL now contains &name=libstdc%2B%2B and the expected results appear