autoname.cc: Return number of renames

Was previously the number of proposed renames, but since renames can be skipped this causes the final count to differ from the number of actually renamed objects.
Check counts in `tests/various/autoname.ys`.

tests/various/autoname.ys

@@ -18,6 +18,7 @@ module \top
 end
 EOT
 logger -expect log "Rename cell .name in top to y_.and_Y" 1
+logger -expect log "Renamed 1 objects" 1
 debug autoname
 logger -check-expected
 
@@ -42,6 +43,7 @@ module \top
 end
 EOT
 logger -expect log "Rename cell .name in top to ab_.or_A" 1
+logger -expect log "Renamed 1 objects" 1
 debug autoname
 logger -check-expected
 
@@ -78,6 +80,7 @@ end
 EOT
 logger -expect log "Rename cell .name in top to bcd_.and_B" 1
 logger -expect log "Rename cell .name2 in top to c_has_a_long_name_.or_B" 1
+logger -expect log "Renamed 2 objects" 1
 debug autoname
 logger -check-expected
 
@@ -113,6 +116,7 @@ end
 EOT
 logger -expect log "Rename cell .name in top to y_.and_Y" 1
 logger -expect log "Rename cell .name2 in top to y_.and_Y_1" 1
+logger -expect log "Renamed 2 objects" 1
 debug autoname
 logger -check-expected
 
@@ -174,6 +178,7 @@ EOT
 # wires are named for being cell outputs
 logger -expect log "Rename wire .d in top to or_Y" 1
 logger -expect log "Rename cell .name2 in top to or_Y_.or_B" 1
+logger -expect log "Renamed 2 objects" 1
 debug autoname t:$or
 logger -check-expected
 
@@ -186,5 +191,6 @@ logger -expect log "Rename cell .name3 in top to or_Y_.or_B_Y_.and_B" 1
 # $c gets shortest name, since the cell driving it doesn't have known port
 # directions
 logger -expect log "Rename wire .c in top to or_Y_.or_B_A" 1
+logger -expect log "Renamed 4 objects" 1
 debug autoname
 logger -check-expected