Correct grammar in list in how-to docs

This commit corrects the grammar in a list in the how-to docs; namely,
the word "and" was missing preceding the final element in a list.

Relates #22663

docs/reference/how-to.asciidoc

@@ -4,7 +4,7 @@
 [partintro]
 --
 Elasticsearch ships with defaults which are intended to give a good out of
-the box experience. Full text search, highlighting, aggregations, indexing
+the box experience. Full text search, highlighting, aggregations, and indexing
 should all just work without the user having to change anything.
 
 Once you better understand how you want to use Elasticsearch, however,