add function get_current_content_type to output class and user manual library
diff --git a/user_guide_src/source/libraries/output.rst b/user_guide_src/source/libraries/output.rst
index 2cf7c08..8cd5ff8 100644
--- a/user_guide_src/source/libraries/output.rst
+++ b/user_guide_src/source/libraries/output.rst
@@ -49,6 +49,13 @@
.. important:: Make sure any non-mime string you pass to this method
exists in config/mimes.php or it will have no effect.
+$this->output->get_current_content_type();
+====================================
+
+Get the current mime-type of your page and return 'text/html' by default.
+
+ $this->output->get_current_content_type();
+
$this->output->get_output();
=============================