docs(faqs): worker note in datastore entry

docs/faqs.md

@@ -34,9 +34,11 @@ Then run `texts` again. Then use the [variable update](scl.md#dealing-with-failu
 ```python
 from virtmat.middleware.resconfig import get_resconfig_loc, get_default_resconfig
 cfg = get_default_resconfig()
-wcfg = cfg.workers[0]
+wcfg = cfg.workers[0] # SEE NOTE
 wcfg.envvars.update({'DATASTORE_CONFIG': '/alternative/path_to/my_project/datastore_config.yaml'})
 wcfg.default_envvars.append('DATASTORE_CONFIG')
 cfg.default_worker = wcfg
 cfg.to_file(get_resconfig_loc())
 ```
+
+**NOTE:** In this example `worker[0]` is assumed as the relevant worker for the datastore configuration. If available, other workers can be selected by using the corresponding index, eg `worker[n]`.
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