Add spector test for SpecialWords_ReservedOperationBodyParams withItems scenario

[Copilot]

The SpecialWords_ReservedOperationBodyParams_withItems scenario was missing from specialWords.spec.ts despite the special-words path already being registered in azureModularTsps and the generated client already exposing reservedOperationBodyParams.withItems.

Changes

• specialWords.spec.ts — adds a ReservedOperationBodyParams describe block with the withItems test case:
  • POSTs { "items": ["item"] } to /special-words/operations/body-param-reserved
  • Asserts 204 No Content (void return)

describe("ReservedOperationBodyParams", () => {
  it("should post withItems", async () => {
    await client.reservedOperationBodyParams.withItems(["item"]);
  });
});

This verifies that an operation parameter named items (a reserved Python dict method name) is sent on the wire as items, not mangled to items_property or similar.