Digits (#3073)

* Digits

* digits widget

* update requires str

* digits docs

* simplify

* tweak docs

* snapshot test

* change name

* simplify

* docs

* Update _digits.py superfluous import

* Update _digits.py docstring

* address review

* formatting

* Update tests/snapshot_tests/snapshot_apps/digits.py

Co-authored-by: Dave Pearson <davep@davep.org>

---------

Co-authored-by: Dave Pearson <davep@davep.org>

docs/examples/widgets/digits.py

@@ -0,0 +1,22 @@
+from textual.app import App, ComposeResult
+from textual.widgets import Digits
+
+
+class DigitApp(App):
+    CSS = """
+    Screen {
+        align: center middle;
+    }
+    #pi {
+        border: double green;
+        width: auto;
+    }
+    """
+
+    def compose(self) -> ComposeResult:
+        yield Digits("3.141,592,653,5897", id="pi")
+
+
+if __name__ == "__main__":
+    app = DigitApp()
+    app.run()