Adds correct definition refs #2814

Author: JJ

doc/Type/independent-routines.pod6

@@ -442,7 +442,11 @@ See also L<C<new>|/type/Proc#method_new> for more examples.
 
 =head2 sub shell
 
-    sub shell($cmd --> Proc)
+=begin code
+multi sub shell($cmd, :$in = '-', :$out = '-', :$err = '-',
+                Bool :$bin, Bool :$chomp = True, Bool :$merge,
+                Str :$enc, Str:D :$nl = "\n", :$cwd = $*CWD, :$env)
+=end code
 
 Runs a command through the system shell, which defaults to
 C<%*ENV<ComSpec> /c> in Windows, C</bin/sh -c> otherwise. All shell meta
@@ -455,8 +459,8 @@ The return value is of L<type Proc|/type/Proc>.
 
     shell 'ls -lR | gzip -9 > ls-lR.gz';
 
-See L<Proc|/type/Proc#method_shell> for more details, for example on how to capture
-output.
+See L<Proc|/type/Proc#method_shell> for more details, for example on how to
+capture output.
 
 =end pod