[DOCS] Adds release highlight for #33471 (#35442)

Author: lcawl

docs/reference/release-notes/highlights-6.5.0.asciidoc

@@ -6,4 +6,15 @@
 
 coming[6.5.0]
 
-See also <<release-notes-6.5.0,{es} 6.5.0 release notes>>. 
+See also <<release-notes-6.5.0,{es} 6.5.0 release notes>>. 
+
+[float]
+=== Discover the structure of text files
+
+experimental[] The new <<ml-find-file-structure,find file structure API>> 
+determines the structure of a text file. It also returns statistics about the 
+most common values of the detected fields and mappings that you can use when you 
+ingest the file into {es}. If you want to influence the output, you can specify 
+optional parameters. For example, if the file contains semi-structured text, you 
+can specify a Grok pattern or let the tool generate it. This API is also used by 
+the new File Data Visualizer in {kib}.