"Die with more informative messages on unuspported protocols"

LWP::Simple currently dies with cryptic error messages when invoked without the "http://" part in the URI. See the following terminal output :

simula67@hades ~ » perl -e "use LWP::Simple; LWP::Simple.getprint('https://www.google.com');"
501 Protocol scheme 'https' is not supported (LWP::Protocol::https not installed) <URL:https://www.google.com>
simula67@hades ~ » perl -e "use LWP::Simple; LWP::Simple.getprint('www.google.com');" 
400 URL must be absolute <URL:www.google.com>

simula67@hades ~/repos/perl6/3test » cat test.pl6 
#!/opt/perl6/bin/perl6
use LWP::Simple;
my $url = @*ARGS[0] // "http://www.rakudo.org";
LWP::Simple.getprint($url);

simula67@hades ~/repos/perl6/3test » ./test.pl6 www.google.com
No such method 'lc' for invocant of type 'Any'
  in method scheme at /opt/perl6/lib/parrot/5.9.0/languages/perl6/lib/URI.pm:138
  in method parse_url at /opt/perl6/lib/parrot/5.9.0/languages/perl6/lib/LWP/Simple.pm:297
  in method request_shell at /opt/perl6/lib/parrot/5.9.0/languages/perl6/lib/LWP/Simple.pm:40
  in method get at /opt/perl6/lib/parrot/5.9.0/languages/perl6/lib/LWP/Simple.pm:29
  in method getprint at /opt/perl6/lib/parrot/5.9.0/languages/perl6/lib/LWP/Simple.pm:268
  in block  at ./test.pl6:4

#With the change

simula67@hades ~/repos/perl6/3test » ./test.pl6 www.google.com                                   
400 URL must be absolute <URL:www.google.com>

  in method request_shell at /home/simula67/repos/perl6-lwp-simple/lib/LWP/Simple.pm:39
  in method get at /home/simula67/repos/perl6-lwp-simple/lib/LWP/Simple.pm:29
  in method getprint at /home/simula67/repos/perl6-lwp-simple/lib/LWP/Simple.pm:270
  in block  at ./test.pl6:4

simula67@hades ~/repos/perl6/3test » ./test.pl6 https://www.google.com
501 Protocol scheme 'https' is not supported  <URL:https://www.google.com>

  in method request_shell at /home/simula67/repos/perl6-lwp-simple/lib/LWP/Simple.pm:40
  in method get at /home/simula67/repos/perl6-lwp-simple/lib/LWP/Simple.pm:29
  in method getprint at /home/simula67/repos/perl6-lwp-simple/lib/LWP/Simple.pm:270
  in block  at ./test.pl6:4