message: Fix completionItem.range when the current char is '\'
diff: @@ -73,7 +73,7 @@ export class Command implements IProvider {
  const useOptionalArgsEntries = configuration.get('intellisense.optionalArgsEntries.enabled')
  let range: vscode.Range | undefined = undefined
  if (document && position) {
  - const startPos = document.lineAt(position).text.lastIndexOf('\\', position.character)
  + const startPos = document.lineAt(position).text.lastIndexOf('\\', position.character - 1)
  if (startPos >= 0) {
  range = new vscode.Range(position.line, startPos + 1, position.line, position.character)
  }
  