Fix strip_app to always rewrap in a list (#2124)

Author: garazdawi

lib/ex_doc/language/erlang.ex

@@ -418,15 +418,15 @@ defmodule ExDoc.Language.Erlang do
   end
 
   defp strip_app([{:code, attrs, [code], meta}], app) do
-    [{:code, attrs, strip_app(code, app), meta}]
+    [{:code, attrs, List.wrap(strip_app(code, app)), meta}]
   end
 
   defp strip_app(code, app) when is_binary(code) do
-    String.trim_leading(code, "//#{app}/")
+    List.wrap(String.trim_leading(code, "//#{app}/"))
   end
 
   defp strip_app(other, _app) do
-    other
+    List.wrap(other)
   end
 
   defp warn_ref(href, config) do