Union is not considered private by --ctags

[andy-hanson]

In the following example, U is not considered private:

private alias a = int;
private int i;
private void f() {}
private class C {}
private struct S {}
private union U {}

If I run dub run dscanner -- --ctags a.d, I get:

!_TAG_FILE_FORMAT	2
!_TAG_FILE_SORTED	1
!_TAG_FILE_AUTHOR	Brian Schott
!_TAG_PROGRAM_URL	https://github.com/dlang-community/D-Scanner/
C	a.d	4;"	c	line:4	access:private
S	a.d	5;"	s	line:5	access:private
U	a.d	6;"	u	line:6
a	a.d	1;"	a	line:1	access:private
f	a.d	3;"	f	line:3	access:private	signature:()
i	a.d	2;"	v	line:2	access:private