message: use char range where possible
diff: @@ -21,7 +21,7 @@ impl_webpage! {
  }
  pub fn sitemapindex_handler(req: &mut Request) -> IronResult<Response> {
  - let sitemaps: Vec<char> = (b'a'..=b'z').map(char::from).collect();
  + let sitemaps: Vec<char> = ('a'..='z').collect();
  SitemapIndexXml { sitemaps }.into_response(req)
  }
  @@ -216,7 +216,7 @@ mod tests {
  assert!(!(content.contains(&"some_random_crate_that_failed")));
  // and not in the others
  - for letter in ('a'..='z').filter(|&&c| c != 's') {
  + for letter in ('a'..='z').filter(|&c| c != 's') {
  let response = web
  .get(&format!("/-/sitemap/{}/sitemap.xml", letter))
  .send()?;
  