message: Update manifest.md
  clearer example
diff: @@ -364,7 +364,8 @@ script guide.
  ```toml
  [package]
  # ...
  -links = "foo"
  +# this package links with a native library called "git2", e.g. "libgit2.a" on Linux
  +links = "git2"
  ```
  <a id="the-exclude-and-include-fields-optional"></a>
  