message: Update how-to-run-planning.md
  plug in the actual link to the Inside Rust blog post template.
diff: @@ -56,4 +56,4 @@ google calendar and selecting "publish".
  Add a blog post to the Inside Rust blog using the [template found on
  the compiler-team repository][blog-template].
  -[blog-template]: XXX
  +[blog-template]: https://github.com/rust-lang/compiler-team/blob/master/templates/planning-meeting-blog-post.md
  