milestone 13 discrepancies: redact credentials from urls in logs, metrics and cli output

docs/how-to/install-with-docker.md

@@ -73,13 +73,28 @@ database has nothing to forward to. The log is
 `no configuration file at '/etc/nxdns/config.zon'; using the database as it is`
 followed by `nxdns run failed: NoUsableUpstreams`.
 
-A file that is present but rejected is a different failure and a different exit
+A file that is present but rejected is a different failure with the same exit
 code. No `default` group, no enabled upstream, a syntax error — `run` prints the
-diagnostic and exits **1**, for example `nxdns run failed: MissingDefaultGroup`.
-Both were run here against this image: a seed file whose only group was named
-`other` exited 1, and an empty `/etc/nxdns` exited 2 with `NoUsableUpstreams`.
-Under `restart: unless-stopped` either one is a restart loop, so read the exit
-code from `docker inspect` to tell them apart; see
+diagnostic and exits 2 as well. Both were run here against this image. A seed
+file whose only group was named `other`:
+
+```
+FAIL groups: no group named 'default'; every unknown client is assigned to it
+nxdns run failed: MissingDefaultGroup
+run `nxdns check` to see the configuration in full
+```
+
+and an empty `/etc/nxdns`:
+
+```
+info(config_bootstrap): no configuration file at '/etc/nxdns/config.zon'; using the database as it is
+nxdns run failed: NoUsableUpstreams
+run `nxdns check` to see the configuration in full
+```
+
+Under `restart: unless-stopped` either one is a restart loop, and the exit code
+alone no longer tells them apart: read the lines above the failure, which either
+name the diagnostic in the file or say there was no file at all. See
 [Troubleshoot nxdns](troubleshoot.md).
 
 The container runs as uid 65532, and the mount is read-only, so the container