Fix: Add return type declarations

src/RuleSet.php

@@ -20,14 +20,14 @@ interface RuleSet
      *
      * @return string
      */
-    public function name();
+    public function name(): string;
 
     /**
      * Returns an array of rules along with their configuration.
      *
      * @return array
      */
-    public function rules();
+    public function rules(): array;
 
     /**
      * Returns the minimum required PHP version (PHP_VERSION_ID).
@@ -36,5 +36,5 @@ public function rules();
      *
      * @return int
      */
-    public function targetPhpVersion();
+    public function targetPhpVersion(): int;
 }

test/Unit/FactoryTest.php

@@ -99,10 +99,7 @@ public function testFromRuleSetCreatesConfig(int $targetPhpVersion): void
         self::assertSame($rules, $config->getRules());
     }
 
-    /**
-     * @return \Generator
-     */
-    public function providerTargetPhpVersion()
+    public function providerTargetPhpVersion(): \Generator
     {
         $values = [
             \PHP_VERSION_ID - 1,

test/Unit/RuleSet/AbstractRuleSetTestCase.php

@@ -107,10 +107,7 @@ final public function testHeaderCommentFixerIsEnabledIfHeaderIsProvided($header)
         self::assertSame($expected, $rules['header_comment']);
     }
 
-    /**
-     * @return \Generator
-     */
-    final public function providerValidHeader()
+    final public function providerValidHeader(): \Generator
     {
         $values = [
             'string-empty' => '',
@@ -145,10 +142,7 @@ final public function testRulesAreSortedByName($source, $ruleNames): void
         ));
     }
 
-    /**
-     * @return \Generator
-     */
-    final public function providerRuleNames()
+    final public function providerRuleNames(): \Generator
     {
         $values = [
             'rule set' => self::createRuleSet()->rules(),