DOC: compression: chunk are not compressed anymore

Add the chunk issue to the list of non-working cases.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 712afff..1d13c1e 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -1991,6 +1991,8 @@
       "Accept-Encoding" header
     * the response message is not HTTP/1.1
     * HTTP status code is not 200
+    * response header "Transfer-Encoding" contains "chunked" (Temporary
+      Workaround)
     * response contain neither a "Content-Length" header nor a
       "Transfer-Encoding" whose last value is "chunked"
     * response contains a "Content-Type" header whose first value starts with