feat: silence progress with --quiet

src/output.rs

@@ -1,9 +1,13 @@
-// progress and warnings go to stderr, so what a caller pipes is only ever the
-// data a command was asked for
+// progress, on stderr and only when it was asked for
 macro_rules! note {
-    ($($arg:tt)*) => { eprintln!($($arg)*) };
+    ($ctx:expr, $($arg:tt)*) => {
+        if !$ctx.quiet {
+            eprintln!($($arg)*)
+        }
+    };
 }
 
+// not progress: it speaks about the result, so --quiet keeps it
 macro_rules! warning {
     ($($arg:tt)*) => { eprintln!("warning: {}", format_args!($($arg)*)) };
 }