Rename `Screenreaders` to "Screen readers".

No redirect is added because the next version will be a minor version bump.

site/_data/nav.yml

@@ -66,7 +66,7 @@
     - title: Image replacement
     - title: Overflow
     - title: Position
-    - title: Screenreaders
+    - title: Screen readers
     - title: Shadows
     - title: Sizing
     - title: Spacing

site/docs/4.2/utilities/screenreaders.md → site/docs/4.2/utilities/screen-readers.md

 ---
 layout: docs
-title: Screenreaders
-description: Use screenreader utilities to hide elements on all devices except screen readers.
+title: Screen readers
+description: Use screen reader utilities to hide elements on all devices except screen readers.
 group: utilities
 ---