[docs] add missing observability settings to example config (#1790)

example/config.yaml

@@ -766,11 +766,37 @@ syslog-address: "localhost:514"
 ##### OBSERVABILITY SETTINGS #####
 ##################################
 
+# Bool. Enable generation/parsing of a request ID for each received HTTP Request.
+# Default: true
+request-id-enabled: true
+
 # String. Header name to use to extract a request or trace ID from. Typically set by a
 # loadbalancer or proxy.
 # Default: "X-Request-Id"
 request-id-header: "X-Request-Id"
 
+# Bool. Enable OpenTelemetry based tracing support.
+# Default: false
+tracing-enabled: false
+
+# String. Set the transport protocol for the tracing system. Can either be "grpc" for
+# OTLP gRPC or "jaeger" for jaeger based ingesters.
+# Options: ["grpc", "jaeger"]
+# Default: "grpc"
+tracing-transport: "grpc"
+
+# String. Endpoint of the trace ingester. When using the gRPC based transport, the
+# endpoint is usually a single address/port combination. For the jaeger transport it
+# should be a fully qualified URL.
+# OTLP gRPC or "jaeger" for jaeger based ingesters
+# Examples: ["localhost:4317", "http://localhost:14268/api/traces"]
+# Default: ""
+tracing-endpoint: ""
+
+# Bool. Disable HTTPS for the gRPC transport protocol.
+# Default: false
+tracing-insecure-transport: false
+
 #############################
 ##### ADVANCED SETTINGS #####
 #############################