fix provisioner metric docs (#4359)

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>
25 jobs for master in 45 minutes and 52 seconds (queued for 13 seconds)
Name Stage Failure
failed
zombienet-tests-malus-dispute-valid Deploy


exit code 1
+ EXIT_STATUS=1
+ set +x

2021-11-24 15:04:06 - INFO - Exit status is 1
Cleaning up file based variables
ERROR: Job failed: command terminated with exit code 1
failed
spellcheck Test
[2021-11-24T14:15:23Z INFO  cargo_spellcheck::action] ✅ /builds/parity/polkadot/runtime/parachains/src/disputes/benchmarking.rs
[2021-11-24T14:15:23Z INFO cargo_spellcheck::action] ✅ /builds/parity/polkadot/runtime/parachains/src/initializer/benchmarking.rs
[2021-11-24T14:15:23Z INFO cargo_spellcheck::action] ✅ /builds/parity/polkadot/runtime/parachains/src/runtime_api_impl/v1.rs

real 1m25.740s
user 5m12.668s
sys 1m19.188s
Cleaning up file based variables
ERROR: Job failed: exit code 1