Make BaseGroovyExtension and BaseKotlinExtension public

Author: Goooler

plugin-gradle/CHANGES.md

@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `3.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Make `BaseGroovyExtension` and `BaseKotlinExtension` public. ([#1912](https://github.com/diffplug/spotless/pull/1912))
 
 ## [6.23.0] - 2023-11-27
 ### Added

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/BaseGroovyExtension.java

@@ -27,7 +27,7 @@
 import com.diffplug.spotless.groovy.RemoveSemicolonsStep;
 import com.diffplug.spotless.java.ImportOrderStep;
 
-abstract class BaseGroovyExtension extends FormatExtension {
+public abstract class BaseGroovyExtension extends FormatExtension {
 	protected BaseGroovyExtension(SpotlessExtension spotless) {
 		super(spotless);
 	}

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/BaseKotlinExtension.java

@@ -33,7 +33,7 @@
 import com.diffplug.spotless.kotlin.KtLintStep;
 import com.diffplug.spotless.kotlin.KtfmtStep;
 
-abstract class BaseKotlinExtension extends FormatExtension {
+public abstract class BaseKotlinExtension extends FormatExtension {
 	protected BaseKotlinExtension(SpotlessExtension spotless) {
 		super(spotless);
 	}