mouse: set mouse to text when bypassing mouse reporting

When shift is held, we are bypassing mouse reporting mode. Change the
cursor to text to indicate this to the user. On release, change back to
whatever we were before.

src/Surface.zig

@@ -1121,6 +1121,17 @@ pub fn keyCallback(
         self.hideMouse();
     }
 
+    if (self.io.terminal.flags.mouse_event != .none and
+        event.physical_key == .left_shift or
+        event.physical_key == .right_shift)
+    {
+        switch (event.action) {
+            .press => try self.rt_surface.setMouseShape(.text),
+            .release => try self.rt_surface.setMouseShape(self.io.terminal.mouse_shape),
+            else => {},
+        }
+    }
+
     // No binding, so we have to perform an encoding task. This
     // may still result in no encoding. Under different modes and
     // inputs there are many keybindings that result in no encoding

src/termio/Exec.zig

@@ -2024,6 +2024,7 @@ const StreamHandler = struct {
         self: *StreamHandler,
         shape: terminal.MouseShape,
     ) !void {
+        self.terminal.mouse_shape = shape;
         _ = self.ev.surface_mailbox.push(.{
             .set_mouse_shape = shape,
         }, .{ .forever = {} });