Custom file icon overrides icon themes

[texastoland]

#77 introduced a custom file icon. Although neat it overrides file icon themes by default. AFAIK the only way to prevent that behavior is to add showLanguageModeIcons: false (like https://github.com/lineville/vscode-emoji-icons/blob/8e6cdc77686316dcdcd8b6142542299310ccd971/file-icons/emoji-icon-theme.json#L2) to each theme itself. The problem arises that many themes (like https://github.com/EliverLara/sweet-vscode-icons) are unmaintained. It's arguably VS Code's fault for not exposing a user toggle but unpleasant nonetheless.