Enhancing error message when referring @private / @local from other module.

[alexveden]

When calling the left module (@Private / @Local) code from the right module:

 6:
 7: fn void test_add() {
 8:
 9:     assert(4 == foo::add_priv(4, 4));
                         ^^^^^^^^
(test_foo.c3:9:22) Error: 'foo::add_priv' could not be found, did you perhaps want 'foo::add'?

 7: fn void test_add() {
 8:
 9:     assert(4 == foo::add_priv(4, 4));
10:     assert(4 == foo::add_local(4, 4));
                         ^^^^^^^^^
(test_foo.c3:10:22) Error: 'foo::add_local' could not be found, did you perhaps want 'foo::add'?

Maybe it could be more informative to refer to these members as @Private / @Local in error messages?

[lerno]

Local is going to be hard, since that one is not usually placed anywhere. But at least we can improve @private