Implement passing the bell signal to the terminal

src/tests/fixtures/ring_bell

@@ -0,0 +1,6 @@
+[?2004h
+zellij on  main [!] is 📦 v0.24.0 via 🦀 v1.57.0 
+❯ ❯ bell
+[?2004l[?2004h
+zellij on  main [!] is 📦 v0.24.0 via 🦀 v1.57.0 took 5s 
+❯ 

zellij-server/src/panes/grid.rs

@@ -399,6 +399,7 @@ pub struct Grid {
     pub title: Option<String>,
     pub is_scrolled: bool,
     pub link_handler: LinkHandler,
+    pub ring_bell: bool,
     scrollback_buffer_lines: usize,
 }
 
@@ -446,6 +447,7 @@ impl Grid {
             changed_colors: None,
             is_scrolled: false,
             link_handler: Default::default(),
+            ring_bell: false,
             scrollback_buffer_lines: 0,
         }
     }
@@ -1506,6 +1508,9 @@ impl Perform for Grid {
 
     fn execute(&mut self, byte: u8) {
         match byte {
+            7 => {
+                self.ring_bell = true;
+            }
             8 => {
                 // backspace
                 self.move_cursor_back(1);

zellij-server/src/panes/terminal_pane.rs

@@ -273,6 +273,11 @@ impl Pane for TerminalPane {
                 }
                 character_styles.clear();
             }
+            if self.grid.ring_bell {
+                let ring_bell = '\u{7}';
+                vte_output.push(ring_bell);
+                self.grid.ring_bell = false;
+            }
             self.set_should_render(false);
             Some(vte_output)
         } else {

zellij-server/src/panes/unit/grid_tests.rs

@@ -1078,3 +1078,15 @@ pub fn full_screen_scroll_region_and_scroll_up() {
     grid.scroll_up_one_line();
     assert_snapshot!(format!("{:?}", grid));
 }
+
+#[test]
+pub fn ring_bell() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(134, 64, Palette::default());
+    let fixture_name = "ring_bell";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert!(grid.ring_bell);
+}