Document Esc and Ctrl bracket mode exits

src/input.zig

@@ -290,3 +290,15 @@ test "adversarial: replay names first event mismatch" {
         .ok => return error.ExpectedTraceDivergence,
     }
 }
+
+test "regular: Ctrl-[ normalizes as escape" {
+    try std.testing.expectEqual(Event{ .key = .escape }, normalize("\x1b"));
+}
+
+test "regular: Ctrl-[ trace labels as escape" {
+    var recorder = TraceRecorder.init(std.testing.allocator);
+    defer recorder.deinit();
+
+    try recorder.capture("\x1b");
+    try std.testing.expect(std.mem.indexOf(u8, recorder.text(), "escape") != null);
+}