fix - high-contrast mode - sidebar needs visual separation

- Due to how high-contrast mode works, there was no visual separation between the sidebar and the main content, adding a transparent border resolves this without having any visual impact in non-high contrast mode
- fixes #7456

CHANGELOG.txt

@@ -27,8 +27,7 @@ Changelog
  * Fix: Remove redundant 'clear' button from site root page chooser (Matt Westcott)
  * Fix: Make ModelAdmin IndexView keyboard-navigable (Saptak Sengupta)
  * Fix: Prevent error on refreshing page previews when multiple preview tabs are open (Alex Tomkins)
- * Fix: Admin fields and Icon visibility issues in Windows high contrast mode (Dmitrii Faiazov)
- * Fix: Add visual separation between the Page Editor's field panels on Windows high contrast mode (Chakita Muttaraju)
+ * Fix: Multiple accessibility fixes for Windows high contrast mode; Admin fields, Icon visibility, Page Editor field panels, sidebar menu (Dmitrii Faiazov, Chakita Muttaraju, Onkar Apte, LB (Ben Johnston))
  * Fix: `blocks.MultipleChoiceBlock`, `forms.CheckboxSelectMultiple` and `ArrayField` checkboxes will now stack instead of display inline to align with all other checkboxes fields (Seb Brown)
  * Fix: Screen readers can now access login screen field labels (Amy Chan)
  * Fix: Admin breadcrumbs home icon now shows for users with access to a subtree only (Stefan Hammer)

CONTRIBUTORS.rst

@@ -533,6 +533,7 @@ Contributors
 * Chakita Muttaraju
 * Fabien Le Frapper
 * Jonathan "Yoni" Knoll
+* Onkar Apte
 
 Translators
 ===========

client/scss/components/_main-nav.scss

@@ -10,6 +10,7 @@
 
     .inner {
         background: $nav-grey-1;
+        border-right: 1px solid transparent; // ensure visible separation in Windows High Contrast mode
 
         @include media-breakpoint-up(sm) {
             // On medium, make it possible for the nav links to scroll.

docs/releases/2.15.rst

@@ -42,8 +42,7 @@ Bug fixes
  * Remove redundant 'clear' button from site root page chooser (Matt Westcott)
  * Make ModelAdmin IndexView keyboard-navigable (Saptak Sengupta)
  * Prevent error on refreshing page previews when multiple preview tabs are open (Alex Tomkins)
- * Admin fields and Icon visibility issues in Windows high contrast mode (Dmitrii Faiazov)
- * Add visual separation between the Page Editor's field panels on Windows high contrast mode (Chakita Muttaraju)
+ * Multiple accessibility fixes for Windows high contrast mode; Admin fields, Icon visibility, Page Editor field panels, sidebar menu (Dmitrii Faiazov, Chakita Muttaraju, Onkar Apte, LB (Ben Johnston))
  * ``blocks.MultipleChoiceBlock``, ``forms.CheckboxSelectMultiple`` and ``ArrayField`` checkboxes will now stack instead of display inline to align with all other checkboxes fields (Seb Brown)
  * Screen readers can now access login screen field labels (Amy Chan)
  * Admin breadcrumbs home icon now shows for users with access to a subtree only (Stefan Hammer)