Describe new 'ant.import' extension point
Describe new 'ant.import' extension point

Per dita-ot/dita-ot#2766

Signed-off-by: Roger Sheen <a61a1add71dadc74037ae5e44ee30713db9a7451@infotexture.net>

dita-ot/docs,infotexture/docs,shaneataylor/docs,shaneataylor/docs,infotexture/docs