text: Title: Recognize library classes decorated with `@library` decorator regardless their name
  Body: project structure:
  ``` shell
  my_module
      sub_module
          lib.py
          __init__.py
      __init__.py
  test.robot
  ```
  `lib.py`
  ``` python
  from robot.api.deco import library, keyword
  
  @library(scope="GLOBAL")
  class lib:
  
      @keyword
      def my_py_kw(self):
          print("foo")
  ```
  
  `test.robot`
  ``` robot
  *** Settings ***
  Library    my_module.sub_module.lib
  
  *** Test Cases ***
  example
      my py kw
  ```
  
  when I change the lib class from `class lib` to `class Foo`, the kw `my_py_kw ` will not be recognized anymore.
  
  I think once I used the deco `@library` for a lib class, robot should use this deco to detect lib class instead of only using the name.