[00200200]

Fixes #536.

Formatting {#if true /* condition */}{/if} currently removes the comment. Svelte attaches it to trailingComments, outside the expression's end position. Include those comments in the text passed to Prettier. Add a line-suffix boundary so a trailing // comment stays inside the Svelte expression instead of becoming literal markup after its closing brace.

The new JS and TS fixtures cover conditionals, each/await/key blocks, attributes, HTML tags, multiple trailing comments, comments inside parentheses, and line comments. The formatting harness also checks a second formatting pass.

Validation on Node 20.19.5, locked Svelte 5.56.0 and Prettier 3.8.3:

• Both new regression fixtures fail on unchanged base commit 7809486 and pass with the fix.
• pnpm test: 311 tests passed.
• pnpm build, pnpm lint, and git diff --check: passed.
• Built-plugin smoke tests preserve the reported block comment and a trailing line comment; a second pass is unchanged.
• pnpm check fails with missing estree declarations and three resulting implicit-any errors. The unchanged base has the same four errors with the same installed dependencies.

Scope: this preserves trailing comments attached to embedded nodes by the Svelte compiler. Comments the compiler leaves unattached, such as a comment after an expression's closing parenthesis, are outside this fix. The additional CI dependency versions have not been run locally.

AI disclosure: OpenAI Codex investigated the issue, prepared the code and tests, and wrote this PR description at the account owner's request. No human code review took place during this session.