Explain that JSON events are parsed (#14203)

* Explain that JSON events are parsed

Some customers are seeing issue in v2 monitors because their JSON event is getting parsed automatically by Datadog and text search does not work for event attribute. (They need to manually add Facet for automatically parsed event attribute to make it work.) 
Need to clarify that like Logs document.
Logs document says "Datadog automatically parses JSON-formatted logs. When logs are not JSON-formatted, you can add value to your raw logs by sending them through a processing pipeline."

* Update content/en/events/guides/migrating_to_new_events_features.md

Co-authored-by: Heston Hoffman <[email protected]>

Co-authored-by: Heston Hoffman <[email protected]>

Author: Sayumi-n

content/en/events/guides/migrating_to_new_events_features.md

@@ -76,7 +76,7 @@ The new query search allows you to use complex queries in event monitors with ne
 
 ### Pipelines
 
-With pipelines, events are parsed and enriched by chaining them sequentially through processors. Processors extract meaningful information or attributes from semi-structured text to reuse as facets. Each event that comes through the pipelines is tested against every pipeline filter. If it matches a filter, then all the processors are applied sequentially before moving to the next pipeline.
+Datadog automatically parses JSON-formatted events. When events are not JSON-formatted, they are parsed and enriched by chaining them sequentially through a processing pipeline. Processors extract meaningful information or attributes from semi-structured text to reuse as facets. Each event that comes through the pipelines is tested against every pipeline filter. If it matches a filter, then all the processors are applied sequentially before moving to the next pipeline.
 
 ## What Changed?