message: Fix non english stemmers
diff: use super::{Token, TokenFilter, TokenStream};
  use rust_stemmers::{self, Algorithm};
  -use std::sync::Arc;
  /// Available stemmer languages.
  #[derive(Debug, Serialize, Deserialize, Eq, PartialEq, Copy, Clone)]
  @@ -57,14 +56,14 @@ impl Language {
  /// Tokens are expected to be lowercased beforehand.
  #[derive(Clone)]
  pub struct Stemmer {
  - stemmer_algorithm: Arc<Algorithm>,
  + stemmer_algorithm: Algorithm,
  }
  impl Stemmer {
  /// Creates a new Stemmer `TokenFilter` for a given language algorithm.
  pub fn new(language: Language) -> Stemmer {
  Stemmer {
  - stemmer_algorithm: Arc::new(language.algorithm()),
  + stemmer_algorithm: language.algorithm(),
  }
  }
  }
  @@ -83,7 +82,7 @@ where
  type ResultTokenStream = StemmerTokenStream<TailTokenStream>;
  fn transform(&self, token_stream: TailTokenStream) -> Self::ResultTokenStream {
  - let inner_stemmer = rust_stemmers::Stemmer::create(Algorithm::English);
  + let inner_stemmer = rust_stemmers::Stemmer::create(self.stemmer_algorithm);
  StemmerTokenStream::wrap(inner_stemmer, token_stream)
  }
  }
  