make contents_diff include bell state

i don't think it makes sense for contents_formatted to include this

1 files changed, 20 insertions, 0 deletions

diff --git a/src/term.rs b/src/term.rs
index 1e69d07..c988702 100644
--- a/src/term.rs
+++ b/src/term.rs
@@ -344,3 +344,23 @@ impl BufWrite for MoveFromTo {
         }
     }
 }
+
+#[derive(Default, Debug)]
+#[must_use = "this struct does nothing unless you call write_buf"]
+pub struct AudibleBell;
+
+impl BufWrite for AudibleBell {
+    fn write_buf(&self, buf: &mut Vec<u8>) {
+        buf.push(b'\x07');
+    }
+}
+
+#[derive(Default, Debug)]
+#[must_use = "this struct does nothing unless you call write_buf"]
+pub struct VisualBell;
+
+impl BufWrite for VisualBell {
+    fn write_buf(&self, buf: &mut Vec<u8>) {
+        buf.extend_from_slice(b"\x1bg");
+    }
+}