[6.0] 229e1da0b Typo

[Dridi Boukelmoune]

commit 229e1da0b384d66aae247ef6dd96dea11983cd31
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Wed Sep 12 11:53:59 2018 +0200

    Typo

diff --git a/doc/sphinx/reference/vmod.rst b/doc/sphinx/reference/vmod.rst
index b824a26ec..f314527a6 100644
--- a/doc/sphinx/reference/vmod.rst
+++ b/doc/sphinx/reference/vmod.rst
@@ -534,7 +534,7 @@ but still per vmod as for ordinary vmod functions. Thus, vmods
 requiring per-task / per top-request state for object instances need
 to implement other means to associate storage with object instances.
 
-Using ``VRT_priv_task()`` to maintin per object instance state is a
+Using ``VRT_priv_task()`` to maintain per object instance state is a
 convenient yet unofficial interface which was not originally intended
 for this purpose and will likely be replaced with a more suitable
 interface.