feat(shortcode): enable cross-referencing audio

Adds id param to audio shortcode

Hashes are prefixed in the form `#audio-<ID>`

E.g. add `id="my-talk"` when calling the audio shortcode and then reference it using [link to my talk audio](#audio-my-talk)

.editorconfig

@@ -16,5 +16,5 @@ max_line_length = 100
 [*.md]
 trim_trailing_whitespace = false
 
-[{layouts/shortcodes/*.html, layouts/_default/_markup/*.html}]
+[{*/layouts/shortcodes/*.html, */layouts/_default/_markup/*.html}]
 insert_final_newline = false