Update docs/index.asciidoc

Co-authored-by: Ry Biesemeyer <[email protected]>

Author: colinsurprenant

docs/index.asciidoc

@@ -71,7 +71,11 @@ https://github.com/jmettraux/rufus-scheduler#parsing-cronlines-and-time-strings[
 [id="plugins-{type}s-{plugin}-auth"]
 ==== Authentication
 
-Authentication to a secure Elasticsearch cluster is possible using one of the `user`/`password`, `cloud_auth` or `api_key` options.
+Authentication to a secure Elasticsearch cluster is possible using _one_ of the following options:
+
+* <<plugins-{type}s-{plugin}-user>> AND <<plugins-{type}s-{plugin}-password>>
+* <<plugins-{type}s-{plugin}-cloud_auth>>
+* <<plugins-{type}s-{plugin}-api_key>>
 
 
 [id="plugins-{type}s-{plugin}-options"]
@@ -332,4 +336,4 @@ empty string authentication will be disabled.
 [id="plugins-{type}s-{plugin}-common-options"]
 include::{include_path}/{type}.asciidoc[]
 
-:default_codec!:
+:default_codec!: