Repository: prometheus/prometheus (language: go)

Issue:
BUG: nomad_sd_configs does not support "datacenter" key
### What did you do?

Tried using `nomad_sd_configs` according to documentation at https://prometheus.io/docs/prometheus/latest/configuration/configuration/#nomad_sd_config `prom/promtheus:latest` does not start with the following error:

```
$ promtool check config /local/prometheustest.yml
Checking /local/prometheustest.yml
  FAILED: parsing YAML file /local/prometheustest.yml: yaml: unmarshal errors:
  line 17: field datacenter not found in type nomad.plain
```

datacenter is missing in https://github.com/prometheus/prometheus/blob/49f775d8a0d76532fae36c0392d929bbf110577a/discovery/nomad/nomad.go#L76-L84

compared to consul.go https://github.com/prometheus/prometheus/blob/49f775d8a0d76532fae36c0392d929bbf110577a/discovery/consul/consul.go#L112-L121

### What did you expect to see?

_No response_

### What did you see instead? Under which circumstances?

```
$ promtool check config /local/prometheustest.yml
Checking /local/prometheustest.yml
  FAILED: parsing YAML file /local/prometheustest.yml: yaml: unmarshal errors:
  line 17: field datacenter not found in type nomad.plain
```

### System information

Linux Ubuntu 22.04

### Prometheus version

```text
prometheus, version 2.41.0 (branch: HEAD, revision: c0d8a56c69014279464c0e15d8bfb0e153af0dab)
  build user:       root@d20a03e77067
  build date:       20221220-10:40:45
  go version:       go1.19.4
  platform:         linux/amd64
```


### Prometheus configuration file

```yaml
global:
  scrape_interval: 15s
  scrape_timeout: 10s
  evaluation_interval: 15s

scrape_configs:
- job_name: prometheus
  static_configs:
  - targets:
    - localhost:9090

- job_name: service-metrics
  sample_limit: 10000
  scheme: http
  nomad_sd_configs:
    - server: 'http://172.30.195.6:4646'
      datacenter: 'dc1'
```


### Alertmanager version

_No response_

### Alertmanager configuration file

_No response_

### Logs

_No response_


Discussion / hints:

Fix patch:
diff --git a/docs/configuration/configuration.md b/docs/configuration/configuration.md
index 058a33da263..dee7cfce87e 100644
--- a/docs/configuration/configuration.md
+++ b/docs/configuration/configuration.md
@@ -2418,7 +2418,6 @@ The following meta labels are available on targets during [relabeling](#relabel_
 # The information to access the Nomad API. It is to be defined
 # as the Nomad documentation requires.
 [ allow_stale: <boolean> | default = true ]
-[ datacenter: <string> ]
 [ namespace: <string> | default = default ]
 [ refresh_interval: <duration> | default = 60s ]
 [ region: <string> | default = global ]


Test patch: