Accessibility: Fix header icon opacity with high contrast theme

Signed-off-by: Jan-Christoph Borchardt <hey@jancborchardt.net>

apps/accessibility/css/themehighcontrast.scss

@@ -18,6 +18,8 @@ $color-border: darken($color-main-background, 50%);
 $color-border-dark: darken($color-main-background, 50%);
 
 [class^='icon-'], [class*=' icon-'],
-.action {
+.action,
+#appmenu li a,
+.menutoggle {
 	opacity: 1 !important;
 }