Run checkstyle on all source sets

Had an issue last week where testFixtures had a couple of issues which I
didn't pick up on, as the pre-commit hooks only check the main and test
source set.

We now add a per-project "checkstyle" task, which dependes on the
per-source-set checkstyle tasks.

.pre-commit-config.yaml

@@ -44,7 +44,7 @@ repos:
     name: Check Java codestyle
     files: ".*\\.java$"
     language: system
-    entry: ./gradlew checkstyleMain checkstyleTest
+    entry: ./gradlew checkstyle
     pass_filenames: false
     require_serial: true
   - id: illuaminate

CONTRIBUTING.md

@@ -100,7 +100,6 @@ about how you can build on that until you've covered everything!
 [new-issue]: https://github.com/cc-tweaked/CC-Tweaked/issues/new/choose "Create a new issue"
 [community]: README.md#community "Get in touch with the community."
 [Adoptium]: https://adoptium.net/temurin/releases?version=17 "Download OpenJDK 17"
-[checkstyle]: https://checkstyle.org/
 [illuaminate]: https://github.com/SquidDev/illuaminate/ "Illuaminate on GitHub"
 [weblate]: https://i18n.tweaked.cc/projects/cc-tweaked/minecraft/ "CC: Tweaked weblate instance"
 [docs]: https://tweaked.cc/ "CC: Tweaked documentation"

buildSrc/src/main/kotlin/cc-tweaked.java-convention.gradle.kts

@@ -174,6 +174,12 @@ project.plugins.withType(CCTweakedPlugin::class.java) {
     }
 }
 
+tasks.register("checkstyle") {
+    description = "Run Checkstyle on all sources"
+    group = LifecycleBasePlugin.VERIFICATION_GROUP
+    dependsOn(tasks.withType(Checkstyle::class.java))
+}
+
 spotless {
     encoding = StandardCharsets.UTF_8
     lineEndings = LineEnding.UNIX