Highlight the space at the end of each line. It is convenient to use spaces as new line in markdown notation. (I've never seen a markdown file with spaces as new line except me)

• Highlight the space at the end of each line
• You can change the highlight color
• When you save a document, save one space or three or more spaces as two spaces
• Only works if the current document's Language Mode is Markdown

1. Install this extension from vscode
2. Open a markdown file
3. Edit the document and make sure spaces are highlighted
4. Change the highlight color to your liking
5. Enjoy!

This extension provides the following command. Let's write in settings.json.

{
    "workbench.colorCustomizations": {
        "twoOrMoreSpaceHighlight": "#FFFFFF"
    }
}

• If you're opening a markdown file but doesn't work, make sure the Language Mode in the bottom right corner of the editor is "Markdown".

• If all the spaces in each line have removed when you save a document, you can avoid it by the following setting.

{
    "[markdown]": {
        "files.trimTrailingWhitespace": false,
    }
}

here

This extension was created with reference to vscode-extension-samples.