Let a type mapper cover several types at once

[TomasVotruba]

Follow-up to #8230.

Why the duplication could not be removed before

Eight mappers were byte-identical to a sibling except for the PHPStan type they named:

AccessoryLiteralStringTypeMapper   AccessoryNonEmptyStringTypeMapper
AccessoryNonFalsyStringTypeMapper  AccessoryNumericStringTypeMapper    -> all map to "string"

HasOffsetTypeMapper                HasOffsetValueTypeTypeMapper
NonEmptyArrayTypeMapper            OversizedArrayTypeMapper            -> all map to "array"

The obvious fix — one mapper registered against a shared parent type — does not work here. All eight share exactly the same ancestors:

AccessoryLiteralStringType   ancestors: AccessoryType, CompoundType, Type
HasOffsetType                ancestors: AccessoryType, CompoundType, Type

AccessoryType covers both groups, but one group maps to string and the other to array, so no single class-string separates them. getNodeClass(): string was the blocker.

The change

Widen the contract to return several classes:

-    /**
-     * @return class-string<TType>
-     */
-    public function getNodeClass(): string;
+    /**
+     * A mapper can cover several types at once, when they all map to the same output,
+     * e.g. every accessory string type maps to "string"
+     *
+     * @return array<class-string<TType>>
+     */
+    public function getNodeClasses(): array;

Not a new shape for the codebase — NodeTypeResolverInterface next door already declares getNodeClasses(): array and is dispatched the same way.

The two groups then collapse to AccessoryStringTypeMapper and AccessoryArrayTypeMapper: 8 classes to 2.

NeverTypeMapper and ResourceTypeMapper are identical too, but never and resource are unrelated concepts — merging them would shorten the file count and nothing else, so they stay apart.

Cost

Every remaining mapper gains one bracket pair:

-    public function getNodeClass(): string
+    public function getNodeClasses(): array
     {
-        return VoidType::class;
+        return [VoidType::class];
     }

29 files, mechanical. Net -170 lines.

Behavior

Checked, not assumed. I ran all eight collapsed types through the container's PHPStanStaticTypeMapper on this branch and on main, comparing the phpdoc node plus the PhpParser node for PARAM, RETURN and PROPERTY kinds — 32 outputs, all identical.

To make sure the two runs really executed different code (a shared vendor/ autoloader would otherwise resolve both to the same sources), the baseline ran in a separate worktree with a checkout-first autoloader prepended. It demonstrably loaded main's AccessoryLiteralStringTypeMapper, and rejected this branch's AccessoryStringTypeMapper against main's narrower interface.

TypeMapperOrderTest from #8230 is updated for the widened contract and still guards registration order across every declared class.

[TomasVotruba]

LGTM 👍