`cabal build -v` prints one line to stderr

reproducable with both 1.22.6.0 and HEAD when building Cabal library itself. same symptom for other packages.

everything else is printed to stdout, so i guess this is not intended.

Start by running `cabal build -v` while building the Cabal library and another package, capturing stdout and stderr separately. Trace the command's verbose-output path to identify the single stderr line; done means verbose output is consistently written to stdout for both reported versions and package types, with regression coverage where the project permits.

Written by the indexing model from the issue text.