[Testing] Check fixtures use *.php.inc suffix, not bare *.inc

[TomasVotruba]

yieldFilesFromDirectory() defaults to a *.php.inc suffix, so a fixture named *.inc is silently never executed. 8 such files existed in the repo — including 2 accidental file-manager duplicates named * copy.inc.

Script change

scripts/no-php-file-in-fixtures.php already rejected *.php files in Fixture/. It now also rejects any *.inc that is not *.php.inc, and covers tests/ in addition to rules-tests/.

     private function findIncompleteIncFiles(array $directories): array
     {
         $finder = new Finder()
             ->files()
             ->in($directories)
             ->path('/Fixture')
             ->notPath('Source')
+            ->name('*.inc')
+            ->notName('*.php.inc')

Output on the offending state:

 [ERROR] The following files were found in /Fixtures directory, but only
         "*.php.inc" files are picked up and allowed. Rename their suffix or
         remove them

 * rules-tests/Arguments/.../ArgumentAdderRector/Fixture/skip_named_arguments.inc
 * rules-tests/Php73/.../SetcookieRector/Fixture/skip_non_integer_third_arg.inc
 * rules-tests/Php83/.../JsonValidateRector/Fixture/skip_json_validate_invalid_depth.php copy.inc
 * rules-tests/Php85/.../ArrayFirstLastRector/Fixture/skip_as_assign_variable.inc
 * rules-tests/TypeDeclaration/.../AddParamTypeBasedOnPHPUnitDataProviderRector/Fixture/skip_with_nested_method.inc
 * rules-tests/TypeDeclaration/.../BoolReturnTypeFromBooleanStrictReturnsRector/Fixture/skip_possible_void.inc
 * rules-tests/TypeDeclaration/.../ReturnUnionTypeRector/Fixture/change_nullable_union_different_in_parent.php copy.inc
 * tests/Issues/InlineTags/Fixture/with_punctuation.inc

Fixture triage

6 renamed to *.php.inc and now run — all pass, so this recovers real coverage that was dead:

• ArgumentAdderRector/Fixture/skip_named_arguments
• SetcookieRector/Fixture/skip_non_integer_third_arg
• JsonValidateRector/Fixture/skip_json_validate_invalid_depth (was .php copy.inc)
• ArrayFirstLastRector/Fixture/skip_as_assign_variable
• AddParamTypeBasedOnPHPUnitDataProviderRector/Fixture/skip_with_nested_method
• BoolReturnTypeFromBooleanStrictReturnsRector/Fixture/skip_possible_void

1 had a stale expectation — tests/Issues/InlineTags/Fixture/with_punctuation.php.inc. Its expected output predates #6674 and dropped part of the docblock text. Actual current output is correct (text preserved verbatim), so the expectation was corrected to match:

- * @copyright Some Value. {@link https://example.com}.
+ * @copyright Some Value. Something.({@link https://example.com}).

1 removed — ReturnUnionTypeRector/Fixture/change_nullable_union_different_in_parent.php copy.inc. Never passed: it expects ReturnUnionTypeRector to add ?\stdClass where the parent declares the same return, which the rule does not do. Unimplemented-feature WIP, not a regression guard, so it is deleted rather than revived.