use slightly preferred variant

Author: coke

doc/Language/modules-extra.pod6

@@ -26,7 +26,7 @@ Some tests of module quality.
 
 =item L<Test::META|https://modules.perl6.org/dist/Test::META>      Test your META6.json file
 =item L<Test::Output|https://modules.perl6.org/dist/Test::Output>  Test the output to STDOUT and STDERR your program generates
-=item L<Test::Screen|https://modules.perl6.org/dist/Proc::Screen>  Use B<GNU screen> to test fullscreen VT applications
+=item L<Test::Screen|https://modules.perl6.org/dist/Proc::Screen>  Use B<GNU screen> to test full screen VT applications
 =item L<Test::When|https://modules.perl6.org/dist/Test::When>  Control when your tests are run (author testing, online testing, etc.)
 
 =head1 NativeCall