feat: Integrate BufWriteCmd for "write" command

[xiyaowong]

• Works
• Remote
  
• Add tests
• Update readme

close #2075

[theol0403]

I found an edge behavior, not sure if this is intentional or a minor bug.

If you make a change, then undo it, you are back to the last saved version but the vscode dirty status is still enabled. However, running :wall doesn't clear that dirty status (like it used to). :w properly clears it.

[xiyaowong]

I found an edge behavior, not sure if this is intentional or a minor bug.

If you make a change, then undo it, you are back to the last saved version but the vscode dirty status is still enabled. However, running :wall doesn't clear that dirty status (like it used to). :w properly clears it.

This needs to be done in a separate PR. Once the document modifications are synchronized, updating this status will suffice. Additionally, even if a special circumstance causes the status to be incorrect, it's okay; it's not very important.

[xiyaowong]

I have updated the README. Please review