Update/add missing period to doc (#23343)

* Update/add missing period to doc

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

diff --git a/packages/flutter/lib/src/widgets/image.dart b/packages/flutter/lib/src/widgets/image.dart
index b6c2a9a..6684bb2 100644
--- a/packages/flutter/lib/src/widgets/image.dart
+++ b/packages/flutter/lib/src/widgets/image.dart
@@ -472,9 +472,10 @@
   /// If non-null, this color is blended with each image pixel using [colorBlendMode].
   final Color color;
 
-  /// Used to set the filterQuality of the image
-  /// Use the "low" quality setting to scale the image, which corresponds to
-  /// bilinear interpolation, rather than the default "none" which corresponds
+  /// Used to set the [FilterQuality] of the image.
+  ///
+  /// Use the [FilterQuality.low] quality setting to scale the image with
+  /// bilinear interpolation, or the [FilterQuality.none] which corresponds
   /// to nearest-neighbor.
   final FilterQuality filterQuality;