[io grant] Remove tip to use $*SPEC to detect OS

We have $*DISTRO for that purpose

Author: zoffixznet

doc/Language/variables.pod6

@@ -1094,7 +1094,7 @@ X<|$*SPEC>X<|$*TMPDIR>X<|$*THREAD>X<|$*SCHEDULER>
     ------------------+--------------------------------------------
     $*KERNEL          | Which kernel am I running under?
     ------------------+--------------------------------------------
-    $*DISTRO          | Which OS distribution am I running under?
+    $*DISTRO          | Which OS distribution am I running under? (e.g. C<say "Some sort of Windows" if $*DISTRO.is-win>)
     ------------------+--------------------------------------------
     $*VM              | Which virtual machine am I running under?
     ------------------+--------------------------------------------
@@ -1130,8 +1130,7 @@ X<|$*SPEC>X<|$*TMPDIR>X<|$*THREAD>X<|$*SCHEDULER>
                       | "home directory" cannot be determined it will be L<Any>
     ------------------+--------------------------------------------
     $*SPEC            | The appropriate L<IO::Spec> sub-class for the platform that
-                      | the program is running on. For OS-specific code, use smartmatch:
-                      | C<say "We are on Windows!" if $*SPEC ~~ IO::Spec::Win32>
+                      | the program is running on.
     ------------------+--------------------------------------------
     $*TMPDIR          | An L<IO::Path> object representing the "system temporary directory"
     ------------------+--------------------------------------------