Add Github link support to beta and experimental macros

README.asciidoc

@@ -1479,7 +1479,13 @@ Text about old functionality...
 == Experimental and Beta
 
 APIs or parameters that are experimental or in beta can be marked as such, using
-markup similar to that used in <<changes>>.  For instance:
+markup similar to that used in <<changes>>.
+
+In the block format, you have the option of adding a related GitHub issue. If
+both custom text and a GitHub issue are provided, the GitHub issue **must** be
+provided second.
+
+For instance:
 
 [source,asciidoc]
 ----------------------------------
@@ -1488,8 +1494,12 @@ markup similar to that used in <<changes>>.  For instance:
 
 experimental::[]
 
+experimental::[https://github.com/elastic/docs/issues/505]
+
 experimental::[Custom text goes here]
 
+experimental::[Custom text goes here,https://github.com/elastic/docs/issues/505]
+
 Text about new feature...
 
 [[old-feature]]
@@ -1510,10 +1520,13 @@ a new experimental parameter:
 
 experimental::[]
 
+experimental::[https://github.com/elastic/docs/issues/505]
+
 experimental::[Custom text goes here]
 
-Text about new feature...
+experimental::[Custom text goes here,https://github.com/elastic/docs/issues/505]
 
+Text about new feature...
 [[old-feature]]
 === Established feature
 
@@ -1532,8 +1545,12 @@ a new experimental parameter:
 
 beta::[]
 
+beta::[https://github.com/elastic/docs/issues/505]
+
 beta::[Custom text goes here]
 
+beta::[Custom text goes here,https://github.com/elastic/docs/issues/505]
+
 Text about new feature...
 
 [[old-beta-feature]]
@@ -1554,8 +1571,12 @@ a new beta parameter:
 
 beta::[]
 
+beta::[https://github.com/elastic/docs/issues/505]
+
 beta::[Custom text goes here]
 
+beta::[Custom text goes here,https://github.com/elastic/docs/issues/505]
+
 Text about new feature...
 
 [[old-beta-feature]]

resources/asciidoctor/lib/care_admonition/extension.rb

@@ -34,7 +34,7 @@ def activate(registry)
   # Block care admonition.
   class ChangeAdmonitionBlock < Asciidoctor::Extensions::BlockMacroProcessor
     use_dsl
-    name_positional_attributes :passtext
+    name_positional_attributes :passtext, :github
 
     def initialize(role, default_text)
       super(nil)
@@ -43,9 +43,25 @@ def initialize(role, default_text)
     end
 
     def process(parent, _target, attrs)
+      text = attrs[:passtext]
+      gh_pattern = %r{^https?:\/\/github\.com\/elastic\/\S+[^\/]\/issues\/\d+$}
+      if text&.match(gh_pattern)
+        github_link = attrs[:passtext]
+        text = @default_text
+      else
+        github_link = attrs[:github]
+        text ||= @default_text
+      end
+      if github_link
+        github_issue = github_link.split('/').last
+        github_text = <<~TEXT
+          For feature status, see #{github_link}[\##{github_issue}].
+          TEXT
+        text += ' ' + github_text
+      end
       Asciidoctor::Block.new(
         parent, :admonition,
-        source: attrs[:passtext] || @default_text,
+        source: text,
         attributes: {
           'role' => @role,
           'name' => 'warning',