It doesn't make any sense to report this information, since VACUUM
VERBOSE reports on heap relation truncation directly.  This was an
oversight in commit 7ab96cf6, which made VACUUM VERBOSE output a little
more consistent with nearby autovacuum-specific log output.  Adjust
comments that describe how this is supposed to work in passing.

Also bring truncation-related VACUUM VERBOSE output in line with the
convention established for VACUUM VERBOSE output by commit f4f4a649.

Author: Peter Geoghegan <pg@bowt.ie>
Backpatch: 14-, where VACUUM VERBOSE's output changed.