Adds shared attributes for release doc URLs (#1872)

shared/attributes.asciidoc

@@ -303,6 +303,22 @@ Common words and phrases
 :multi-arg: †footnoteref:[multi-arg,This parameter accepts multiple arguments.]
 :multi-arg-ref: †footnoteref:[multi-arg]
 
+//////////
+Issue and pull request URLs
+//////////
+:es-repo: https://github.com/elastic/elasticsearch/
+:es-issue: {es-repo}issues/
+:es-pull: {es-repo}pull/
+:es-commit: {es-repo}commit/
+:kib-repo: https://github.com/elastic/kibana/
+:kib-issue: {kib-repo}issues/
+:kib-pull: {kib-repo}pull/
+:kib-commit: {kib-repo}commit/
+:ml-repo: https://github.com/elastic/ml-cpp/
+:ml-issue: {ml-repo}issues/
+:ml-pull: {ml-repo}pull/
+:ml-commit: {ml-repo}commit/
+
 //////////
 Legacy definitions
 //////////