typo

Author: Ben Skelker

docs/siem/detections/detection-engine-intro.asciidoc

@@ -17,7 +17,7 @@ image::images/detections-ui.png[]
 
 In addition to creating <<rules-ui-create, your own rules>>, enable
 <<load-prebuilt-rules, Elastic prebuilt rules>> to immediately start detecting
-suspicious activity. For detailed information on all the prebuilt rule, see the
+suspicious activity. For detailed information on all the prebuilt rules, see the
 <<prebuilt-rules>> section. Once the prebuilt rules are loaded and
 running, <<tuning-detection-signals>> and <<detections-ui-exceptions>> explain
 how to modify the rules to reduce false positives and get a better set of