message: back to TOML code snippets to fix the CI
diff: //! have to disable the default features and enable whichever you want. For
  //! example, this would compile Rspotify with `reqwest` and the native TLS:
  //!
  -//! ```
  +//! ```toml
  //! [dependencies]
  //! rspotify = {
  //! version = "...",
  //! asynchronous HTTP clients. You can also use `ureq`, a synchronous client,
  //! like so:
  //!
  -//! ```
  +//! ```toml
  //! [dependencies]
  //! rspotify = {
  //! version = "...",
  //! environmental values when using methods like
  //! [`CredentialsBuilder::from_env`](crate::oauth2::CredentialsBuilder::from_env):
  //!
  -//! ```
  +//! ```toml
  //! [dependencies]
  //! rspotify = { version = "...", features = ["env-file"] }
  //! ```
  