Update grok.md (#1404)

Fix minor typo

Author: georgewallace

explore-analyze/scripting/grok.md

@@ -46,7 +46,7 @@ The first value is a number, followed by what appears to be an IP address. You c
 
 To ease migration to the [Elastic Common Schema (ECS)](ecs://reference/index.md), a new set of ECS-compliant patterns is available in addition to the existing patterns. The new ECS pattern definitions capture event field names that are compliant with the schema.
 
-The ECS pattern set has all of the pattern definitions from the legacy set, and is a drop-in replacement. Use the [`ecs-compatability`](logstash-docs-md://lsr/plugins-filters-grok.md#plugins-filters-grok-ecs_compatibility) setting to switch modes.
+The ECS pattern set has all of the pattern definitions from the legacy set, and is a drop-in replacement. Use the [`ecs-compatibility`](logstash-docs-md://lsr/plugins-filters-grok.md#plugins-filters-grok-ecs_compatibility) setting to switch modes.
 
 New features and enhancements will be added to the ECS-compliant files. The legacy patterns may still receive bug fixes which are backwards compatible.