Broken links in README.md

[sadukie]

Describe the bug

The README has two broken links that lead to a rough developer user experience:

• https://github.com/dotnet/systemweb-adapters/blob/main/docs/framework.md - linked under the Set up heading, step 4. I think this is supposed to be linking to a file that shows what's available in FrameworkServices.
• https://github.com/dotnet/systemweb-adapters/blob/main/docs/core.md - linked under the Set up heading, step 5. I think this is supposed to be linking to a file that shows configuration guidance.