docs: add info about remotewrite client config in ruler (#14401)

Co-authored-by: J Stickler <julie.stickler@grafana.com>

docs/sources/operations/recording-rules.md

@@ -74,6 +74,21 @@ so a `Persistent Volume` should be utilised.
 
 ## Remote-Write
 
+### Client configuration
+
+Remote-write client configuration is fully compatible with [prometheus configuration format](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#remote_write).
+
+```yaml
+remote_write:	
+  clients:	
+    mimir:	
+      url: http://mimir/api/v1/push
+      write_relabel_configs:
+      - action: replace
+        target_label: job
+        replacement: loki-recording-rules
+```
+
 ### Per-Tenant Limits
 
 Remote-write can be configured at a global level in the base configuration, and certain parameters tuned specifically on

docs/sources/shared/configuration.md

@@ -4868,7 +4868,9 @@ remote_write:
   # Deprecated: Use 'clients' instead. Configure remote write client.
   [client: <RemoteWriteConfig>]
 
-  # Configure remote write clients. A map with remote client id as key.
+  # Configure remote write clients. A map with remote client id as key. For
+  # details, see
+  # https://prometheus.io/docs/prometheus/latest/configuration/configuration/#remote_write
   [clients: <map of string to RemoteWriteConfig>]
 
   # Enable remote-write functionality.

pkg/ruler/config.go

@@ -53,7 +53,7 @@ func (c *Config) Validate() error {
 
 type RemoteWriteConfig struct {
 	Client              *config.RemoteWriteConfig           `yaml:"client,omitempty" doc:"deprecated|description=Use 'clients' instead. Configure remote write client."`
-	Clients             map[string]config.RemoteWriteConfig `yaml:"clients,omitempty" doc:"description=Configure remote write clients. A map with remote client id as key."`
+	Clients             map[string]config.RemoteWriteConfig `yaml:"clients,omitempty" doc:"description=Configure remote write clients. A map with remote client id as key. For details, see https://prometheus.io/docs/prometheus/latest/configuration/configuration/#remote_write"`
 	Enabled             bool                                `yaml:"enabled"`
 	ConfigRefreshPeriod time.Duration                       `yaml:"config_refresh_period"`
 	AddOrgIDHeader      bool                                `yaml:"add_org_id_header" doc:"description=Add X-Scope-OrgID header in remote write requests."`