Update schema name resolver to remove unnecessary "List" suffix

[greyli]

In my opinion, the List suffix for the OpenAPI schema name is unnecessary.

Assuming we have a User schema. In OpenAPI, an array of User objects will be represented with:

type: array
items:
  $ref: '#/components/schemas/UserList'

Thus, the UserList schema is actually just a User schema. There won't be a conflict between User and User(many=True).

Besides, there is only one schema called UserList generated in spec (not a User schema plus a UserList schema), the user may be confused with this behavior.

[miguelgrinberg]

Yeah, it seems the name does not really matter as apispec will merge the list and non-list versions into the same schema. Thanks.