Generate PR suggestions when formatting is wrong

This should make it much easier to do drive-by changes in the GitHub
editor: the comment should contain a diff that can be committed
directly from the online editor.

.github/workflows/build.yml

@@ -21,14 +21,21 @@ jobs:
         run: |
           sudo apt update
           sudo apt install gettext yapf3
+          curl -fsSL https://dprint.dev/install.sh | sh
+          echo "/home/runner/.dprint/bin" >> $GITHUB_PATH
 
       - name: Install nightly rustfmt
         run: |
           rustup default nightly
           rustup component add rustfmt
 
-      - name: Check formatting
-        uses: dprint/check@v2.2
+      - name: Reformat
+        run: dprint fmt
+
+      - uses: parkerbxyz/suggest-changes@v1
+
+      - name: Check if there were any changes
+        run: git diff --exit-code
 
   typos:
     runs-on: ubuntu-latest

README.md

@@ -43,19 +43,20 @@ Articles and blog posts from around the web which cover Comprehensive Rust:
   _[In Search of Rust Developers, Companies Turn to In-House Training](https://www.darkreading.com/application-security/google-microsoft-take-refuge-in-rust-languages-better-security)_.
   About how Microsoft, Google, and others are training people in Rust.
 
-## Building
+Building
+--------
 
 The course is built using a few tools:
 
-- [mdbook](https://github.com/rust-lang/mdBook)
-- [mdbook-svgbob](https://github.com/boozook/mdbook-svgbob)
+* [mdbook](https://github.com/rust-lang/mdBook)
+* [mdbook-svgbob](https://github.com/boozook/mdbook-svgbob)
 - [mdbook-i18n-helpers and i18n-report](https://github.com/google/mdbook-i18n-helpers)
 - [mdbook-exerciser](mdbook-exerciser/)
 - [mdbook-course](mdbook-course/)
 
 In addition,
 [mdbook-linkcheck](https://github.com/Michael-F-Bryan/mdbook-linkcheck) checks
-the internal links.
+the   internal   links.
 
 First install Rust by following the instructions on https://rustup.rs/. Then
 clone this repository: