Postpone .child -> .child (secure) swap to 6.e

Postponed until 6.e because there's a huge amount of ecosystem usage
and the IO::Path.add that is the alternative is too new for module
authors to reliably switch to using it.

Author: zoffixznet

doc/Type/IO/Path.pod6

@@ -152,7 +152,7 @@ Defined as:
     method child(IO::Path:D: Str() $childname --> IO::Path:D)
 
 Alias for L«C<.add>|/routine/add». B<NOTE:> C<.child> will be switched to
-secure version around 6.d release time, which will C<fail()> with non-child
+secure version around 6.e release time, which will C<fail()> with non-child
 paths and is also slower, since it has to do more work. Use
 L«C<.add>|/routine/add» if your code does not need to guarantee the added
 path is in fact a child path.