The Error enum synthesized declarations, e.g. the struct and its static accessors, should generally appear to be identical to the underlying Clang definitions. There are some specific use cases where the synthesized declarations are necessary though.
I've added an option for USR generation to override the Clang node and emit the USR of the synthesized Swift declaration. This is used by SwiftDocSupport so that the USRs of the synthesized declarations are emitted.
Fixes 79912
* treat children of underscored protocols as public
Children of underscored protocols should be treated as native children
of their conforming types. To accomplish this, ignore underscored
protocols in the isInherentlyPrivate check.
rdar://124483146
* include underscored protocol methods even when skipping protocols
rdar://128143861
