Fix L24T-2.yaml (value of blockLiteral) bug in yaml-test-suite (#18331)

Co-authored-by: fisker <lionkay@gmail.com>

changelog_unreleased/yaml/18331.md

@@ -0,0 +1,16 @@
+#### Fix block value ends with whitespace (#18331 by @kovsu)
+
+```js
+import { inspect } from "node:util";
+import * as prettier from "prettier";
+
+const input = "foo: |\n  x\n   ";
+const output = await prettier.format(input, { parser: "yaml" });
+console.log(inspect(output));
+
+// Prettier stable
+//-> 'foo: |\n  x\n\n'
+
+// Prettier main
+//-> 'foo: |\n  x\n'
+```