NelmioApiDocBundle giving error after installation in Symfony 4?

Question

symfony

$ composer require nelmio/api-doc-bundle
$ composer require nelmio/api-doc-bundle
Using version ^[email protected] for nelmio/api-doc-bundle
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Nothing to install or update
Generating autoload files
ocramius/package-versions:  Generating version class...
ocramius/package-versions: ...done generating version class
Executing script cache:clear [KO]
 [KO]
Script cache:clear returned with error code 1
!!
!!   // Clearing the cache for the dev environment with debug true
!!
!!
!!  In FileLoader.php line 168:
!!

!!    Unable to find file "@NelmioApiDocBundle/Resources/config/routing.yml" in @NelmioApiDocBundle/Resources/config/routing.yml (which is being imported from "C:\Users\BonBon\Code\testsite\config\routes/nelmio_api_doc.yaml"). Make sure the "NelmioApiDocBundle/
R
!!    esources/config/routing.yml" bundle is correctly registered and loaded in the application kernel class. If the bundle is registered, make sure the bundle path "@NelmioApiDocBundle/Resources/config/routing.yml" is not empty.

!!

!!
!!  In Kernel.php line 277:
!!
!!    Unable to find file "@NelmioApiDocBundle/Resources/config/routing.yml".
!!
!!
!!  cache:clear [--no-warmup] [--no-optional-warmers] [-h|--help] [-q|--quiet] [-v|vv|vvv|--verbose] [-V|--version] [--ansi] [--no-ansi] [-n|--no-interaction] [-e|--env ENV] [--no-debug] [--] <command>
!!
!!

Installation failed, reverting ./composer.json to its original content.

How to fix this please tell me?
It will be necessary to generate docks for api.