Fix bezier-vscode bug (#2499)

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about the changes that needed to be released. (or didn't have to)
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## Related Issue

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<!-- Fixes #0000 -->

- None

## Summary

<!-- Please brief explanation of the changes made -->

- bezier-vscode 0.2.0 으로 설치했을 때 자동완성이 안되는 버그를 수정합니다. 

## Details

<!-- Please elaborate description of the changes -->

- 개발 모드에서 실행했을 때 자동완성을 보여줄 때 아래 에러가 떴었습니다. 동작에 문제는 없어서 그대로 배포했으나 배포
환경에서는 자동완성이 안되서 아래 에러와 관련이 있으리라 생각됩니다.

<img width="501" alt="image"
src="https://github.com/user-attachments/assets/262cfe67-b0e0-489a-9b27-f915669c0528">

- 추측하건대 resolveProvider: true 로 해놓고 connection.onCompletionResolve 핸들러를
붙이지 않아서 뜨는 에러 같습니다. onCompletionResolve 는 completion 을 완성했을 때 세부 정보를 붙이는
핸들러라 불필요하다고 판단해서 resolveProvider 자체를 지웠습니다.
- resolveProvider: true 를 넣은 것은 resolveProvider: true 로 해야 자동완성 기능을 지원하는
줄 알았는데 다시 테스트 해보니 completionProvider 가 not null 이면 지원을 하나 봅니다.

### Breaking change? (Yes/No)

<!-- If Yes, please describe the impact and migration path for users -->

- No

## References

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aware of -->

-
https://github.com/microsoft/vscode-extension-samples/blob/727cb7ea42a9258e58b3b919efd8c725a6f8f1e4/lsp-sample/server/src/server.ts#L233-L246

.changeset/fair-timers-jog.md

@@ -0,0 +1,5 @@
+---
+'bezier-vscode': patch
+---
+
+Fix bug where `bezier-vscode` is not running.

packages/bezier-vscode/src/server.ts

@@ -107,9 +107,8 @@ connection.onInitialize(() => {
     capabilities: {
       textDocumentSync: TextDocumentSyncKind.Incremental,
       // Tell the client that this server supports code completion.
-      completionProvider: {
-        resolveProvider: true,
-      },
+      // code completion is not supported if completionProvider is undefined
+      completionProvider: {},
     },
   }