Fixes in catalog component blocks [2.3-develop]

[mhauri]

Description

This PR fixes a few PHPDocs and annotations typos along with wrong return type suggestions.

It also solves an issue with the method Magento\Backend\Block\Widget\Grid\Extended::addColumn() invoking with 3 parameters when only 2 are required. See line 105

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[osrecio]

Hi @mhauri , Thanks for your contribution.

Can you squash your commit ?

Thanks!

[mhauri]

@osrecio not sure how to to that in the aftermath? Is this an Issue?

[osrecio]

Hi @mhauri I sent you a message in engcom slack to explain you how to make a squash.
Is good practice to have only one commit by PR.
Thanks!

[mhauri]

Thank you @osrecio for the help with rebasing. Hope it's fine now.

[osrecio]

Now is fine! I will process your PR asap 😄

[mhauri]

Hi @osrecio anything else required to process this PR?

[osrecio]

No @mhauri , I'm checking internal processes and tests to verify that all is correct. Thanks

[magento-engcom-team]

Hi @mhauri. Thank you for your contribution.
Changes from your Pull Request will be available with the upcoming 2.3.0 release.