debug-delta-find: introduce a quiet mode

In quiet mode, we only print the summary of the search and skip the individual
steps.

mercurial/debugcommands.py

@@ -1021,7 +1021,7 b' def debugdeltafind(ui, repo, arg_1, arg_'
     deltacomputer = deltautil.deltacomputer(
         revlog,
         write_debug=ui.write,
-        debug_search=True,
+        debug_search=not ui.quiet,
     )
 
     node = revlog.node(rev)