Removes comments from shared attributes

Author: lcawl

shared/attributes.asciidoc

@@ -1,4 +1,4 @@
-//URLs
+
 :ref:                  https://www.elastic.co/guide/en/elasticsearch/reference/{branch}
 :ref-80:               https://www.elastic.co/guide/en/elasticsearch/reference/master
 :ref-70:               https://www.elastic.co/guide/en/elasticsearch/reference/7.0
@@ -59,7 +59,6 @@
 :graph-forum:          https://discuss.elastic.co/c/x-pack/graph
 :apm-forum:            https://discuss.elastic.co/c/apm
 
-//Products
 :stack:           Elastic Stack
 :xpack:           X-Pack
 :es:              Elasticsearch
@@ -76,7 +75,6 @@
 :functionbeat:    Functionbeat
 :journalbeat:     Journalbeat
 
-//Features
 :security:                X-Pack security
 :security-features:       security features
 :es-security-features:    {es} {security-features}
@@ -104,7 +102,6 @@
 :ilm-cap:                 Index lifecycle management
 :ilm-init:                ILM
 
-//Machine learning concepts
 :dfeed:              datafeed
 :dfeeds:             datafeeds
 :dfeed-cap:          Datafeed