Enhancement: Enable indentation_type fixer

[localheinz]

This pull request

• enables the indentation_type fixer
• runs make coding-standards

Follows #559.

💁‍♂️ For reference, see https://github.com/FriendsOfPHP/PHP-CS-Fixer/blob/v3.4.0/doc/rules/whitespace/indentation_type.rst.

[cmb69]

Thank you for the PR! Looks good to me.

I'm fine with using four spaces indent instead of tabs, and generally fine with transitioning to PSR-12 (which is likely one of the most common coding standards for PHP OSS projects).

[localheinz]

@cmb69

I believe that the specifics of a coding standard do not matter as long as they can be enforced automatically!

[cmb69]

I believe that the specifics of a coding standard do not matter as long as they can be enforced automatically!

Right! I should have added: ", so we hopefully all can agree on using PSR-12". I wouldn't want to discuss any single rule individually, but rather get this mess somewhat cleaned up. :)

[localheinz]

@cmb69

As an alternative to enabling fixers individually, I have opened #638!

[localheinz]

@cmb69

Rebased!

[localheinz]

Thank you, @cmb69!