Fix typos (flutter#92245)

Author: asashour

packages/flutter/lib/src/material/navigation_bar.dart

@@ -705,7 +705,7 @@ class _DestinationLayoutAnimationBuilder extends StatelessWidget {
 ///
 /// Used by [_NavigationDestinationBuilder].
 class _NavigationBarDestinationSemantics extends StatelessWidget {
-  /// Adds the the appropriate semantics for navigation bar destinations to the
+  /// Adds the appropriate semantics for navigation bar destinations to the
   /// [child].
   const _NavigationBarDestinationSemantics({
     Key? key,

packages/flutter/lib/src/widgets/text_selection.dart

@@ -335,7 +335,7 @@ class TextSelectionOverlay {
   /// A callback that's optionally invoked when a selection handle is tapped.
   ///
   /// The [TextSelectionControls.buildHandle] implementation the text field
-  /// uses decides where the the handle's tap "hotspot" is, or whether the
+  /// uses decides where the handle's tap "hotspot" is, or whether the
   /// selection handle supports tap gestures at all. For instance,
   /// [MaterialTextSelectionControls] calls [onSelectionHandleTapped] when the
   /// selection handle's "knob" is tapped, while