Extractor: Update README.md with --files hint (for --filters placement)

Author: roydejong

README.md

@@ -9,7 +9,7 @@ Hello. Here's some things this fork offers:
 
 - This fork has been designed for **compatibility with version 2 of twig**. It's a bit of a hack, but it works.
 - Removed symfony dependencies which might make it a bit easier to install.
-- You can add "dummy filters" via a `--filter` parameter to prevent the extractor from breaking when it encounters user-defined filters that would cause template parsing to break.
+- You can add "dummy filters" via a `--filter` parameter to prevent the extractor from breaking when it encounters user-defined filters that would cause template parsing to break (HINT: add this *before* the `--files` part of the extractor command).
 - If extraction fails for whatever reason, a log file will be dumped to the directory in which the gettext extractor library lives.
 
 This fork is available on Packagist as a composer package for your convenience: