saveDocument method
Saves the document in the LSP server.
Sends a 'didSave' notification to the LSP server with the current content.
Implementation
Future<void> saveDocument(String content) async {
await _sendNotification(
method: 'textDocument/didSave',
params: {
'textDocument': {'uri': Uri.file(filePath).toString()},
'text': content,
},
);
}