message: refactor: avoid collecting, straight to string
diff: @@ -31,11 +31,12 @@ pub fn read_gene_map(input_gene_map: &Option<PathBuf>, genes: &Option<Vec<String
  let requested_genes_not_in_genemap = genes
  .iter()
  .filter(|&gene_name| !gene_map.contains_key(gene_name))
  - .collect::<Vec<_>>();
  - if requested_genes_not_in_genemap.len() > 0 {
  + .join("`, `");
  + if !requested_genes_not_in_genemap.is_empty() {
  warn!(
  - "The following genes were requested through `--genes` but not found in the gene map: {:?}",
  - requested_genes_not_in_genemap
  + "The following genes were requested through `--genes`\
  + but not found in the gene map:\
  + `{requested_genes_not_in_genemap}`",
  );
  }
  Ok(gene_map)
  @@ -46,7 +47,10 @@ pub fn read_gene_map(input_gene_map: &Option<PathBuf>, genes: &Option<Vec<String
  // Gene list is provided, but no gene map. This is illegal.
  (None, Some(_)) => {
  - make_error!("List of genes via '--genes' can only be specified when a gene map (genome annotation) is provided")
  + make_error!(
  + "List of genes via '--genes' can only be specified\
  + when a gene map (genome annotation) is provided"
  + )
  }
  // Nothing is provided. Create an empty gene map.
  