--- a/modules/stdlib/lib/puppet/parser/functions/is_function_available.rb	Sat Jan 04 11:42:45 2020 +0000
+++ b/modules/stdlib/lib/puppet/parser/functions/is_function_available.rb	Sun Jan 26 11:36:07 2020 +0000
@@ -3,9 +3,16 @@
 #
 module Puppet::Parser::Functions
   newfunction(:is_function_available, :type => :rvalue, :doc => <<-DOC
-    This function accepts a string as an argument, determines whether the
-    Puppet runtime has access to a function by that name.  It returns a
-    true if the function exists, false if not.
+    @summary
+      **Deprecated:** Determines whether the Puppet runtime has access to a function by that name.
+
+    This function accepts a string as an argument.
+
+    @return [Boolean]
+      Returns `true` or `false`
+
+    > **Note:* **Deprecated** Will be removed in a future version of stdlib. See
+    [`validate_legacy`](#validate_legacy).
     DOC
              ) do |arguments|