Remove redundant code, fix incorrect docstring

src/textual/layout.py

@@ -232,7 +232,7 @@ class Layout(ABC):
             widget (Widget): The Widget in this layout you wish to know the Region of.
 
         Raises:
-            KeyError: If the Widget is not contained in this Layout.
+            NoWidget: If the Widget is not contained in this Layout.
 
         Returns:
             Region: The Region of the Widget.

src/textual/view.py

@@ -15,9 +15,6 @@ from .layouts.factory import get_layout
 from .reactive import Reactive, watch
 from .widget import Widget
 
-if TYPE_CHECKING:
-    pass
-
 
 class LayoutProperty:
     def __get__(self, obj: View, objtype: type[View] | None = None) -> str: