Hi!

I noticed one typo in org-manual.org: 'month' value for 'tree-type'
property should not be @code{month} but only 'month'.

Moreover, I added this 'month' value to org-capture-templates
description in org-capture.el.

This is just documentation, but I had to read to code in order to use
this new value (which is awesome).

Feel free to merge this patch if you want!

Cheers,
-- 
Florian