[chore][receiver/signalfx] Mark as deprecated in docs (#7264)

Author: crobert-1

docs/components.md

@@ -69,7 +69,7 @@ The distribution offers support for the following components.
 | [redis](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/receiver/redisreceiver)                                                        | [beta]           |
 | [saphana](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/receiver/saphanareceiver)                                                    | [alpha]          |
 | [scripted_inputs](../internal/receiver//scriptedinputsreceiver)                                                                                                    | [in development] |
-| [signalfx](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/receiver/signalfxreceiver)                                                  | [stable]         |
+| [signalfx](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/receiver/signalfxreceiver)                                                  | [deprecated]     |
 | [signalfxgatewayprometheusremotewrite](https://github.com/signalfx/splunk-otel-collector/tree/main/internal/receiver/signalfxgatewayprometheusremotewritereceiver) | [in development] |
 | [smartagent](../pkg/receiver/smartagentreceiver)                                                                                                                   | [beta]           |
 | [snmp](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/receiver/snmpreceiver)                                                          | [alpha]          |