message: extend explaining comment for crates.io search
diff: @@ -287,8 +287,8 @@ fn get_search_results(
  Ok(SearchResult {
  // start with the original names from crates.io to keep the original ranking,
  - // extend with the release/build information from docs.rs, if we already
  - // know about the crate.
  + // extend with the release/build information from docs.rs
  + // Crates that are not on docs.rs yet will not be returned.
  results: names
  .iter()
  .filter_map(|name| crates.get(name))
  