Add 'issue' attribute for GitLab link inline macro

lib/asciidoctor/gitlab-link-inline-macro/README.adoc

@@ -23,6 +23,9 @@ By default. it doesn't point to anything which should be in the default branch o
 
 - `path` is the filepath to be linked.
 
+- `issue` is the issue to be linked from the repo.
+Take note issue has higher precedence so once `domain` and `issue` are both set, it will still link to an issue.
+
 There are settings that is enabled with the link:https://docs.asciidoctor.org/asciidoc/latest/attributes/options/[options attribute].
 
 - `repo` sets the default caption to be the repo part.

lib/asciidoctor/gitlab-link-inline-macro/extension.rb

@@ -20,8 +20,14 @@ class GitLabLinkInlineMacro < Asciidoctor::Extensions::InlineMacroProcessor
     text = attrs['caption'] || default_caption
     uri = URI.parse %(https://#{attrs['domain']}/#{target})
 
-    uri.path += %(/-/tree/#{attrs['rev']}) if attrs['rev']
-    uri.path += %(/#{attrs['path']}) if attrs['path']
+    if attrs.key? 'issue'
+      uri.path += %(/-/issues/#{attrs['issue']})
+      text << "##{attrs['issue']}" if text == target
+    else
+      uri.path += %(/-/tree/#{attrs['rev']}) if attrs.key? 'rev'
+      uri.path += %(/#{attrs['path']}) if attrs.key? 'path'
+      text << "@#{attrs['rev']}" if attrs.key?('rev') && text == target
+    end
 
     target = uri.to_s