Updated mediawiki/extensions
Project: mediawiki/extensions/BookManagerv2  5bf0a553e8ab689231ea3bc7979d5c5ccca10312

Change NS_MAIN to $wgContentNamespaces.

Per suggestion from helder.wiki, check that the navigation bars
are being added to a namespace in $wgContentNamespaces, instead
of just checking that it's NS_MAIN.

Change-Id: If8c8bb21536ae64765b056fb685ad23b1909c2df