Update _index.md: fix typos (#9782)

Author: beviniy

website/content/en/docs/reference/vrl/_index.md

@@ -120,7 +120,7 @@ acquainted with Vector and VRL:
 VRL is built by the Vector team and its development is guided by two core goals,
 [safety](#safety) and [performance](#performance), without compromising on
 flexibility. This makes VRL ideal for critical, performance-sensitive
-infrastructure, like observabiity pipelines. To illustrate how we achieve these,
+infrastructure, like observability pipelines. To illustrate how we achieve these,
 below is a VRL feature matrix across these principles:
 
 | Feature                                       | Safety | Performance |