devel/cdecl: upgrade to 7.0.

East const
New -E/--east-const command-line and east-const set options to use "east const" in gibberish:

cdecl> declare x as const int
int const x;
Correct scope names for nested types
Previously, scope names for nested types were always printed as "of scope"; now they print the type of scope (class, struct, union, or namespace):

c++decl> struct S { typedef int Int; };
c++decl> explain S::Int x
declare x as Int of structure S
Declare const/volatile user-defined conversion operators
Can now declare const/volatile user-defined conversion operators.

no_unique_address
Added support for the no_unique_address attribute in C++20.

Typename
Now allowing typename in declarations (even though it's not needed):

struct S { typedef int I; };
explain typename S::I x
typedef typename S::I T
throw() deprecated/removed
throw() has been deprecated starting with C++11 and removed in C++20.

Fixed unknown type in typedef
Fixed a crash caused by a case like:

define S as struct S
explain S::T x