Improve config descriptions

  # <config_dir>.

  #oidc_backends_config_file: oidc_backends_config.xml

  # Sets a custom series of steps in the authentication pipeline

  # for OIDC authentication. The default is

  # galaxy.authnz.psa_authnz.AUTH_PIPELINE

  #oidc_auth_pipeline:

  #  - social_core.pipeline.social_auth.social_details

  #  - social_core.pipeline.social_auth.social_uid

  # Sets the full sequence of steps that Python Social Auth goes through

  # when authenticating an OIDC login. Use when you want to completely

  # customize the pipeline (e.g. for testing).

  # By default, Galaxy uses galaxy.authnz.psa_authnz.AUTH_PIPELINE - see

  # there for example steps.

  # Each element should be an import path to a function, e.g.

  # galaxy.authnz.psa_authnz.contains_required_data

  #oidc_auth_pipeline: null

  # Sets additional authentication pipeline steps, added after the

  # default steps (from galaxy.authnz.psa_authnz.AUTH_PIPELINE).

  # Use when you want to keep the default pipeline, but add additional

  # custom processing.

  # Each element should be an import path to a function, e.g.

  # galaxy.authnz.psa_authnz.contains_required_data

  #oidc_auth_pipeline_extra: null

  # Sets the prefix for OIDC scopes specific to this Galaxy instance. If

  # an API call is made against this Galaxy instance using an OIDC

  # default) if enable_failed_jobs_working_directory_cleanup is

  # ``true``. Runs in a Celery task.

  #failed_jobs_working_directory_cleanup_interval: 86400

        desc: |

          Sets the full sequence of steps that Python Social Auth goes

          through when authenticating an OIDC login. Use when

          you want to completely customize the pipeline (e.g. for testing)

          you want to completely customize the pipeline (e.g. for testing).

          By default, Galaxy uses galaxy.authnz.psa_authnz.AUTH_PIPELINE - see

          there for example steps.

          Each element should be an import path to a function,

          e.g. galaxy.authnz.psa_authnz.contains_required_data

        desc: |

          Sets additional authentication pipeline steps, added after the

          default steps (from galaxy.authnz.psa_authnz.AUTH_PIPELINE).

          Use when you want to keep the default pipeline, but add additional

          custom processing.

          Each element should be an import path to a function,

          e.g. galaxy.authnz.psa_authnz.contains_required_data