March : Replace 10 source links with xref links

[Rick-Anderson]

When .NET 9 RTM's, replace links https://source.dot.net/#Microsoft with xref links.

^(?=.*https:\/\/source\.dot\.net)(?!.*--keep--).*

See #30158

[timdeschryver]

@Rick-Anderson if you want, I can go over these and update the ones that I can.

[Rick-Anderson]

@Rick-Anderson if you want, I can go over these and update the ones that I can.

OK, but these are low priority. I'll be you can find more interesting work.