Fix accessibility issues in the docs

[evanSe]

Context

We want to improve the accessibility of the Handsontable documentation.

• Ensure proper keyboard navigation using TAB and Shift+Tab
• Ensure focus is always visible
• Address focus issues in all header navigation menus.
• fix keyboard focus on the light/dark toggle switch.
• Make collapsed sidebar groups tabbable.

How has this been tested?

• tested with lighthouse a11y, axe, accessibility insights
• manually tested

Types of changes

• New feature or improvement (non-breaking change which adds functionality)

Related issue(s):

Affected project(s):

• docs

Checklist:

• I have reviewed the guidelines about Contributing to Handsontable and I confirm that my code follows the code style of this project.
• I have signed the Contributor License Agreement
• My change requires a change to the documentation.

[github-actions]

Launch the local version of documentation by running:

npm run docs:review 5a5e238037fa6785dd9b3ee3d250581a5e2c24a5

[budnix]

Everything looks good 👌 I'll leave a small suggestion about correcting styles for the focus code tabs. Right now it looks like this:

and after adding margin

diff --git a/docs/.vuepress/theme/styles/vuepress-tabs-custom.styl b/docs/.vuepress/theme/styles/vuepress-tabs-custom.styl
index c8a7d09ae..edf0638d5 100644
--- a/docs/.vuepress/theme/styles/vuepress-tabs-custom.styl
+++ b/docs/.vuepress/theme/styles/vuepress-tabs-custom.styl
@@ -35,6 +35,7 @@
       a.tabs-component-tab-a {
         padding: 0.5em 1.2em;
         color: $textColor;
+        margin: 3px 3px 0px 3px;

         &:hover {
           text-decoration: none;
@@ -68,7 +69,7 @@
       border-radius: 0;
     }
   }
-
+
   &.selected-preview .tabs-component-panels {
     background: transparent;
   }

[AMBudnik]

Works well in the official version of documentation