message: cargo build: Simplify help for pkgids
  Drop the full paragraph at the end of the help message in favor of a
  reference to `cargo help pkdid`.
diff: @@ -7,7 +7,7 @@ pub fn cli() -> App {
  .alias("b")
  .about("Compile a local package and all of its dependencies")
  .arg_package_spec(
  - "Package to build",
  + "Package to build (see `cargo help pkgid`)",
  "Build all packages in the workspace",
  "Exclude packages from the build",
  )
  @@ -34,11 +34,6 @@ pub fn cli() -> App {
  .arg_build_plan()
  .after_help(
  "\
  -If the --package argument is given, then SPEC is a package id specification
  -which indicates which package should be built. If it is not given, then the
  -current package is built. For more information on SPEC and its format, see the
  -`cargo help pkgid` command.
  -
  All packages in the workspace are built if the `--all` flag is supplied. The
  `--all` flag is automatically assumed for a virtual manifest.
  Note that `--exclude` has to be specified in conjunction with the `--all` flag.
  