Update dockervolumes.md

Error on title note :)
Upstream-commit: 752c3e9208fc44ca25d9698170d41d28a3005cee
Component: engine

components/engine/docs/sources/userguide/dockervolumes.md

@@ -58,7 +58,7 @@ we change the source code. The directory on the host must be specified as an
 absolute path and if the directory doesn't exist Docker will automatically
 create it for you.
 
-> **Note::** 
+> **Note:** 
 > This is not available from a `Dockerfile` due the portability
 > and sharing purpose of it. As the host directory is, by its nature,
 > host-dependent it might not work all hosts.