[pp-1] Convert Template Preprocess hooks to OOP equivalent

I have attached a list of all of the preprocess functions in core.

📌 Explicitly register template_preprocess callbacks in hook_theme() Postponed is in.

About 110, some already converted now.

I'd prefer splitting this a bit, thoughts:

* One for remaining bits in core/includes? (32, including already convered ones)
* one for views + views_ui (about 25)
* one for system (13)
* one for the remaining ones ? (110 - 32 - 25 -13 = 40)

last chunk still seems pretty big, so maybe split out those that have 4 or more on their own (update, image, file). they all also have include files that can then be removed completely.

For modules, what I'd like to do is move their hook_theme() + the preprocess callbacks into a new ThemeHooks or ${Module}ThemeHooks, that does make it a bit bigger though, but otherwise we have to move it again.

I'd vote for splitting it along the 4 lines you mentioned.

Let's move them to ${Module}ThemeHooks, having files called the same is already causing issues finding the right file.

Let's hold off on splitting the last chunk until we get a look at it, but if anything obvious pops up we can split those out to a new issue pretty easily.

Might need to split this up into more chunks. With deprecations, reflowing of the code and all those references in templates, it's a lot of changes, already at 530 insertions(+), 314 deletions(-) and only did the part of theme.inc that I put in global ThemePreprocess, there's still field templates, pager, breadcrumb, image, menu and more.

Yeah no objection here.

Given the standing issue about removing ModuleServiceProvider I would advise to be cautious about introducing another magic named class

fabiorubim740@outlook.com → made their first commit to this issue’s fork.

There is no magic class name here. It's just on conventions on how hook classes are named

Here is where we are working out the naming convention: 📌 [meta] Clean up hook classes in core Active

Sorry for the misunderstanding: I thought you are converting hooks by themes.

That's on the roadmap but this is only about template preprocess hook after 📌 Explicitly register template_preprocess callbacks in hook_theme() Postponed