closeFile method
Close a file (sends textDocument/didClose).
Implementation
void closeFile(String filePath) {
final serverName = _openFiles.remove(filePath);
if (serverName == null) return;
_fileVersions.remove(filePath);
_servers[serverName]?.sendNotification('textDocument/didClose', {
'textDocument': {'uri': _fileUri(filePath)},
});
}