Error on writing or trying to change to VS Code settings

You need validate the settings.json format, put colons: i.e:

{
    "yaml.schemas": {
        "file:///home/yony/.vscode/extensions/docsmsft.docs-yaml-0.2.4/schemas/toc.schema.json": "/toc\\.yml/i"
    },

    "files.associations": {
        "*.erb": "erb"
    },
    "emmet.includeLanguages": {
        "erb": "html"
    }
}

Change it to Default settings and re-configure it as you want

Add this default settings to your settings.json file

Simple copy and paste

>> Default Settings.json File <<