Use 'raku' command and '.raku' file extension (#3507)

Author: stoned

doc/Type/IO/ArgFiles.pod6

@@ -14,7 +14,7 @@ instance, in this way:
 my $argfiles = IO::ArgFiles.new(@*ARGS);
 .say for $argfiles.lines;
 
-If invoked with C<perl6 io-argfiles.p6 *.p6> it will print the contents of all
+If invoked with C<raku io-argfiles.raku *.raku> it will print the contents of all
 the files with that extension in the directory. However, that is totally
 equivalent to:
 
@@ -41,7 +41,7 @@ examples above can be simplified like so:
     # or
     say $*ARGFILES.slurp;
 
-Save one of the variations above in a file, say C<argfiles.p6>.  Then create
+Save one of the variations above in a file, say C<argfiles.raku>.  Then create
 another file (named, say C<sonnet18.txt> with the contents:
 
 =for code :lang<text>
@@ -50,7 +50,7 @@ Shall I compare thee to a summer's day?
 Running the command
 
 =for code :lang<text>
-$ raku argfiles.p6 sonnet18.txt
+$ raku argfiles.raku sonnet18.txt
 
 will then give the output
 
@@ -66,7 +66,7 @@ sub MAIN () {
     .say for $*ARGFILES.lines;
 }
 
-which can be used as C<cat *.p6 | perl6 argfiles-main.p6>, for instance, is
+which can be used as C<cat *.raku | raku argfiles-main.raku>, for instance, is
 totally equivalent to:
 
 =for code