chore(format): add in formatting to build and CI

.git-blame-ignore-revs

@@ -0,0 +1,2 @@
+# Introduce scalafmt
+7a32dde8ef120673a30f22512b191d6706cc70f1

.github/workflows/actions.yml

@@ -44,6 +44,20 @@ jobs:
       - name: Check Binary Compatibility
         run: ./mill -i --disable-ticker __.mimaReportBinaryIssues
 
+  check-formatting:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - uses: actions/setup-java@v3
+        with:
+          distribution: 'temurin'
+          java-version: 17
+
+      - run: ./mill -i -k __.checkFormat
+
   publish-sonatype:
     if: github.repository == 'com-lihaoyi/scalatags' && contains(github.ref, 'refs/tags/')
     needs: test

build.sc

@@ -6,6 +6,7 @@ import de.tobiasroeser.mill.vcs.version.VcsVersion
 import $ivy.`com.github.lolgab::mill-mima::0.0.13`
 import com.github.lolgab.mill.mima._
 import mill.scalalib.api.Util.isScala3
+import mill.scalalib.scalafmt._
 
 val dottyVersions = sys.props.get("dottyVersion").toList
 
@@ -41,7 +42,7 @@ trait ScalatagsPublishModule extends PublishModule with MimaCheck {
   )
 }
 
-trait Common extends CrossScalaModule {
+trait Common extends CrossScalaModule with ScalafmtModule {
   def millSourcePath = super.millSourcePath / offset
   def ivyDeps = Agg(
     ivy"com.lihaoyi::sourcecode::0.3.0",