[Fix Accessibility] Remove redundant role attribute from sidebar navigation list (npm#1726)

## Accessibility Improvements and UI Refinements ### File Changes: 1. `sidebar.js` - Removed redundant `role="list"` attribute from sidebar navigation container 2. `src/mdx/inline-code.js` - Adjusted inline code font size from 85% to 80% for better visual consistency ### Summary: This PR removes a redundant accessibility role attribute from the sidebar navigation and fine-tunes inline code styling to improve both accessibility compliance and visual presentation. ### Screenshots <img width="732" height="190" alt="image" src="https://github.com/user-attachments/assets/614eef9d-57b9-4895-9b9a-80e5235f6f2e" /> <img width="370" height="310" alt="image" src="https://github.com/user-attachments/assets/d332fcef-4374-402e-9bb0-6acb2cd4aea3" /> <img width="370" height="310" alt="image" src="https://github.com/user-attachments/assets/9ba9c755-2a9f-4144-86aa-603e5307a6d6" />

Author: jpg619

src/components/sidebar.js

@@ -48,7 +48,7 @@ const Sidebar = () => (
  borderColor: 'border.subtle',
  }}
  >
- <Box sx={{display: 'flex', flexDirection: 'column'}} role="list">
+ <Box sx={{display: 'flex', flexDirection: 'column'}}>
  <NavItems />
  </Box>
  </Box>

src/mdx/code.js

@@ -48,7 +48,7 @@ const ClipboardCopy = ({value, ...props}) => {
 export const InlineCode = styled.code`
  padding: 0.2em 0.4em;
  font-family: ${themeGet('fonts.mono')};
- font-size: 85%;
+ font-size: 80%;
  background-color: ${themeGet('colors.neutral.muted')};
  border-radius: ${themeGet('radii.2')};
 `