Minor wording tweaks in conventions page

Author: Mathieu Martin

docs/using-conventions.asciidoc

@@ -54,15 +54,15 @@ Default Elasticsearch convention:
 [float]
 ===== ECS convention for indexing text fields
 
-ECS flips the convention around.
+ECS flips the above convention around.
 
 For monitoring use cases, `keyword` indexing is needed almost exclusively, with
 full text search needed on very few fields.
 Moreover, indexing for full text search on lots of fields, where it's not expected
 to be used is wasteful of resources.
 
 Given these two premises, ECS defaults
-all text indexing to `keyword` at the top level (with very few exceptions).
+all text indexing to `keyword` datatype (with very few exceptions).
 Any use case that requires full text search indexing on additional fields
 can add a {ref}/multi-fields.html[multi-field]
 for full text search. Doing so does not conflict with ECS,