The Documentation namespace (XmlDocumentationProvider, IdStringProvider,
XmlDocLoader) had no test coverage at all, even though XmlDoc is listed
as an implemented C# 1 feature on the wiki Language-Feature-Roadmap.
These tests pin ID-string generation and FindEntity round-trips for the
intricate encodings (nested generic types, `0/``0 type-parameter
references, ref/out @ suffixes, pointer and jagged/multi-dimensional
array forms incl. [0:,0:], conversion operators with the ~ReturnType
suffix, indexers, #ctor) plus XmlDocumentationProvider lookup by ID
string and by entity against a generated doc file. All green.
Assisted-by: Claude:claude-fable-5:Claude Code
Siegfried Pammer
eac6c59a43