Alias of signal in a package

[Blebowski]

It may be good to show a warning when a signal declared in package is aliased by a localy defined signal (similar to e.g. when for loop iterator aliases another definition).

A simple test-case for this:

package my_pkg is

    signal example_signal : natural;

end package;

library work;
use work.my_pkg.all;

entity top is
end entity;

architecture test of top is

    signal example_signal : natural;

begin

    process
    begin
        wait for 1 ns;
        example_signal <= 5;
        wait for 1 ns;
        wait;
    end process;

end architecture;