message: Remove use of deprecated Error::description method
diff: @@ -5,7 +5,6 @@ use crate::util::CargoResult;
  use failure::Fail;
  use opener;
  use std::collections::HashMap;
  -use std::error::Error;
  use std::path::Path;
  use std::process::Command;
  @@ -94,7 +93,7 @@ fn open_docs(path: &Path, shell: &mut Shell) -> CargoResult<()> {
  shell.warn(format!(
  "Couldn't open docs with {}: {}",
  browser.to_string_lossy(),
  - e.description()
  + e
  ))?;
  }
  }
  