Added support for deprecated method alias

[matusvalo]

Steps

• Add yourself to CONTRIBUTORS if you are a new contributor.
• Add a ChangeLog entry describing what your PR does.
• If it's a new feature or an important bug fix, add a What's New entry in
  doc/whatsnew/<current release.rst>.
• Write a good description on what the PR does.

Description

This PR adds support for deprecated methods/functions which are just aliases to new names.
Examples of such methods/functions:

• threading.currentThread
• threading.activeCount
• threading.Condition.notifyAll
• threading.Event.isSet
• threading.Thread.setName
• threading.thread.getName
• threading.Thread.isDaemon
• threading.Thread.setDaemon

Type of Changes

	Type
✓	🐛 Bug fix
	✨ New feature
	🔨 Refactoring
	📜 Docs

Related Issue

Closes #4618

[coveralls]

Coverage increased (+0.002%) to 92.041% when pulling f5356e6 on matusvalo:deprecated_methods into 3d6389b on PyCQA:master.

[Pierre-Sassoulas]

Thank you for this new feature, I have a small remark, before merging but this look great 👍

[matusvalo]

Thank you @Pierre-Sassoulas ! I come here to implement your feedback, but it seems you were faster :-D.