XmlDocLoader's modern-.NET fallback built the ref-pack path from the EXACT runtime
patch version (shared/Microsoft.NETCore.App/10.0.8 -> packs/Microsoft.NETCore.App.Ref/
10.0.8/ref), but the targeting (ref) pack version usually differs from the installed
runtime patch -- e.g. pack 10.0.0 -- and a relocated CI install (DOTNET_INSTALL_DIR)
may carry only a different feature band. The exact-version lookup then missed and the
provider came back null, leaving CoreLib hovers undocumented. Broaden the search:
prefer an exact match, then the newest pack sharing the runtime's major.minor, then
the newest pack present.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Promotes the modern .NET XML-doc lookup from the Avalonia port into the
shared ICSharpCode.Decompiler library so every host (WPF, Avalonia, any
third-party consumer of XmlDocLoader) gets hover/tooltip documentation
for system entities without per-host fallback wiring.