add some more info on module import vs. export

Author: tbrowder

doc/Language/modules.pod6

@@ -159,6 +159,22 @@ tags: C<ALL>, C<DEFAULT> and C<MANDATORY>.
     use MyModule :ALL;     # bag, pants, sunglasses, torch, underpants
     =end code
 
+Note there currently is no way for the user to import a single object if 
+the module author hasn't made provision for that, and it is not an easy
+task at the moment (see RT #127305). One way the author can provide
+such access is to give each C<export> trait its own unique tag.  Then
+the user can either (1) import all objects:
+
+    =begin code
+    use Foo :ALL;
+    =end code
+    
+or (2) import one or more objects selectively:
+
+    =begin code
+    use Foo :s1, :s5;
+    =end code
+
 Notes:
 
 1. The C<:MANDATORY> tag on an exported sub ensures it will be exported
@@ -176,6 +192,9 @@ no matter whether the using program adds any tag or not.
     use MyModule :day, :night; # pants, sunglasses, torch
     =end code
 
+5. Multiple tags in the C<export> trait are not allowed.
+
+
 =head3 UNIT::EXPORT::*
 
 Beneath the surface, C<is export> is adding the symbols to a C<UNIT>