get_maintainer: --r (list reviewer) is on by default

We don't consistenly document the default value next to the option
listing, but we do have a list of defaults here, so let's keep it up to
date.

Cherry picked from Linux commit 4f07510df2e8c47fd65b8ffaaf6c5d334d59d598.
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

scripts/get_maintainer.pl

@@ -748,7 +748,7 @@ Other options:
   --help => show this help information
 
 Default options:
-  [--email --nogit --git-fallback --m --n --l --multiline --pattern-depth=0
+  [--email --nogit --git-fallback --m --r --n --l --multiline --pattern-depth=0
    --remove-duplicates --rolestats]
 
 Notes: