message: Fix a documentation for package.build option.
diff: @@ -18,9 +18,10 @@ build = "build.rs"
  The Rust file designated by the `build` command (relative to the package root)
  will be compiled and invoked before anything else is compiled in the package,
  -allowing your Rust code to depend on the built or generated artifacts. Note that
  -if you do not specify a value for `build` but your package root does contains a
  -`"build.rs"` file, Cargo will compile and invoke this file for you.
  +allowing your Rust code to depend on the built or generated artifacts.
  +By default Cargo looks up for `"build.rs"` file in a package root (even if you
  +do not specify a value for `build`). Use `build = "custom_build_name.rs"` to specify
  +a custom build name or `build = false` to disable automatic detection of the build script.
  Some example use cases of the build command are:
  