improve AbstractPipe docs and IOContext handling as an AbstractPipe #52768
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Following some complains that
AbstractPipedid not mention the functions that comprise its API, I have updated that and some other related details of its subtypes.IOContext{IO}(io)to avoid excess specialization. Any explicitly set parameter should now be inherited by futureIOContextconstructions around it, rather than always directly adopting thetypeof(io.io)type instead as the new parameter.