fix typo

doc/Language/rb-nutshell.pod6

@@ -583,7 +583,7 @@ both C<.each> and C<.map>, but we typically use a C<for> loop directly.
         say "n: $n";
     }
 
-    # Perl 6, mis-using .map
+    # Perl 6, misusing .map
     (0..5).map: -> $n {
         say "n: $n";
     }