fix(policy-devel): update description

[Piskoo]

This PR fixes misalignment in policy develop short description.

Before

Available Commands:
  apply       Apply a policy (create or update)
  create      Create a new policy
  delete      Delete a policy
  describe    Describe a specific policy
  develop     Tools for policy development
Refer to https://docs.chainloop.dev/guides/custom-policies

  list        List policies
  update      Update an existing policy

After

Available Commands:
  apply       Apply a policy (create or update)
  create      Create a new policy
  delete      Delete a policy
  describe    Describe a specific policy
  develop     Tools for policy development
  list        List policies
  update      Update an existing policy