Introduced MaskedInput widget

docs/examples/widgets/masked_input.py

@@ -0,0 +1,32 @@
+from textual.app import App, ComposeResult
+from textual.widgets import Label, MaskedInput
+
+
+class MaskedInputApp(App):
+    # (1)!
+    CSS = """
+    MaskedInput.-valid {
+        border: tall $success 60%;
+    }
+    MaskedInput.-valid:focus {
+        border: tall $success;
+    }
+    MaskedInput {
+        margin: 1 1;
+    }
+    Label {
+        margin: 1 2;
+    }
+    """
+
+    def compose(self) -> ComposeResult:
+        yield Label("Enter a valid credit card number.")
+        yield MaskedInput(
+            template="9999-9999-9999-9999;0",  # (2)!
+        )
+
+
+app = MaskedInputApp()
+
+if __name__ == "__main__":
+    app.run()