[BUG] Markdown file extensions not respected

[Chailotl]

Describe the bug When modifying the setting Markdown File Extensions to show the preview button for .mdx files, it does not work.

Environment

• OS: Windows 10
• VSCode: 1.86.2
• Markdown Preview Enhanced: 0.8.11

To Reproduce Steps to reproduce the behavior:

1. Go to extension settings
2. Click on Markdown File Extensions
3. Include .mdx in the list
4. Don't see a preview button for .mdx files

Expected behavior I should be seeing the preview button for .mdx files.

Screenshots