Release notes placeholder for fix for dart-lang/sdk#51251.

We have code that is uppercasing drive letters in many places due to the analyzer currently treating all paths as case-sensitive. At some point this code has stopped working because vs.Uri.file(pathWithUppercaseDrive).toString() has started lowercasing drive letters.

Our code should handle this, to ensure all drive letters going to the LSP server are normalised to uppercase, as we intended.