added "KCL: Restart Language Server" command to restart the KCL language server

[Gmin2]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• [✅ ] Y

Fix #38

2. What is the scope of this PR (e.g. component or file name):

src/extension.ts
package.json

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• [✅ ] Affects user behaviors

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• [ ✅ ] N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

No

[github-actions]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[Gmin2]

I have read the CLA Document and I hereby sign the CLA

[Peefy]

I've added some comments. @He1pa Can you help review it?

[Gmin2]

I've added some comments. @He1pa Can you help review it?

Any updates @Peefy apart from the formating part

[Peefy]

LGTM