message: Fix awkward comma in sentence.
diff: @@ -20,7 +20,7 @@ The package name is an identifier used to refer to the package. It is used
  when listed as a dependency in another package, and as the default name of
  inferred lib and bin targets.
  -The name must not be empty, use only [alphanumeric] characters or `-` or `_`.
  +The name must use only [alphanumeric] characters or `-` or `_`, and cannot be empty.
  Note that [`cargo new`] and [`cargo init`] impose some additional restrictions on
  the package name, such as enforcing that it is a valid Rust identifier and not
  a keyword. [crates.io][cratesio] imposes even more restrictions, such as
  