add entry for AsciiDoc.py along with warning to Awesome AsciiDoc for those still looking for it

awesome-asciidoc.adoc

@@ -37,6 +37,11 @@ Parse and convert AsciiDoc using these language implementations.
 * https://github.com/bytesparadise/libasciidoc[libasciidoc] - A Golang library for processing AsciiDoc.
 * https://github.com/gmarpons/asciidoc-hs[asciidoc-hs] - A Haskell-based AsciiDoc parser that's designed to be used as a pandoc frontend.
 
+AsciiDoc was originally developed as part of the https://asciidoc-py.github.io[AsciiDoc.py project].
+AsciiDoc.py is now a legacy processor for an older rendition of the AsciiDoc syntax.
+As such, it will not properly handle the language that is being described by AsciiDoc specification.
+Unless you still rely on the AsciiDoc.py toolchain, you should choose a processor that handles the current AsciiDoc syntax.
+
 === Publish
 
 Publish content from AsciiDoc using these build tools and static site generators.