Merge pull request rust-lang#1778 from sgoudham/fix-typo

User Guide: Fix typo 'mbdook' to 'mdbook'

guide/src/guide/creating.md

@@ -97,7 +97,7 @@ So if you have images or other static files, just include them somewhere in the
 
 Once you've written your book, you may want to host it somewhere for others to view.
 The first step is to build the output of the book.
-This can be done with the `mbdook build` command in the same directory where the `book.toml` file is located:
+This can be done with the `mdbook build` command in the same directory where the `book.toml` file is located:
 
 ```sh
 mdbook build
@@ -106,4 +106,4 @@ mdbook build
 This will generate a directory named `book` which contains the HTML content of your book.
 You can then place this directory on any web server to host it.
 
-For more information about publishing and deploying, check out the [Continuous Integration chapter](../continuous-integration.md) for more.
+For more information about publishing and deploying, check out the [Continuous Integration chapter](../continuous-integration.md) for more.