doc: update docs

- add a note to "how it works" section about supported compression
  algorithms

Author: zamazan4ik

website/cue/reference/components/sinks/prometheus_remote_write.cue

@@ -100,6 +100,15 @@ components: sinks: prometheus_remote_write: {
 				values for each name, Vector will only send the last value specified.
 				"""
 		}
+		compression_schemes: {
+			title: "Compression schemes"
+			body:  """
+				Officially according to the [Prometheus Remote-Write specification](\(urls.prometheus_remote_write_spec)),
+				the only supported compression scheme is [Snappy](\(urls.snappy)). However,
+				there are a number of other implementations that do support other schemes. Thus
+				Vector also supports using Gzip and Zstd.
+				"""
+		}
 	}
 
 	telemetry: metrics: {

website/cue/reference/urls.cue

@@ -412,6 +412,7 @@ urls: {
 	prometheus_remote_integrations:             "https://prometheus.io/docs/operating/integrations/#remote-endpoints-and-storage"
 	prometheus_remote_write:                    "https://prometheus.io/docs/prometheus/latest/configuration/configuration/#remote_write"
 	prometheus_remote_write_protocol:           "https://docs.google.com/document/d/1LPhVRSFkGNSuU1fBd81ulhsCPR4hkSZyyBj1SZ8fWOM/edit#heading=h.n0d0vphea3fe"
+	prometheus_remote_write_spec:               "https://prometheus.io/docs/concepts/remote_write_spec/#protocol"
 	protobuf:                                   "https://developers.google.com/protocol-buffers"
 	pulsar:                                     "https://pulsar.apache.org/"
 	pulsar_protocol:                            "https://pulsar.apache.org/docs/en/develop-binary-protocol/"