Improves run docs by adding filehandle argument, closes #2111

Author: JJ

doc/Type/IO.pod6

@@ -394,11 +394,12 @@ See L<Proc|/type/Proc> and L<Proc::Async|/type/Proc::Async> for more details.
 
     sub shell($cmd --> Proc)
 
-Runs a command through the system shell, which defaults to C<%*ENV<ComSpec> /c> in Windows, C</bin/sh -c> otherwise. All shell meta characters are
-interpreted by the shell, including pipes, redirects, environment variable
-substitutions and so on. Shell escapes are a severe security concern and can
-cause confusion with unusual file names. Use L<run|/type/IO#sub_run> if you
-want to be safe.
+Runs a command through the system shell, which defaults to
+C<%*ENV<ComSpec> /c> in Windows, C</bin/sh -c> otherwise. All shell meta
+characters are interpreted by the shell, including pipes, redirects,
+environment variable substitutions and so on. Shell escapes are a severe
+security concern and can cause confusion with unusual file names. Use
+L<run|/type/IO#sub_run> if you want to be safe.
 
 The return value is of L<type Proc|/type/Proc>.