Allow not only a colon as a keyword-text divider in todos.

This makes possible to scan such things as doxygen \todo, @todo
entries where colons cannot be added after a keyword.

Change-Id: I13c757294c94a1f4758e7dc9634a79ea6e91c68f
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>