Merge 'Object-oriented code' page into 'PHP coding standards' page

That sounds like a reasonable plan. I expect the Object-oriented page is newer, maybe added when Drupal 8 was first being developed?

There was also support in Slack for this from larowlan and yesct.

I moved the content, then merged two 'naming' and two 'type hinting' sections. After that I took the liberty of alphabetizing the page by the h2 headings and ensured that all h2 headings had a correct id.

Great job, thanks!
I’d merely suggest renaming the “Naming » Classes” sub-heading → to “Classes, methods and properties”. I was a bit confused by properties missing from the “Naming” sub-menu.

@drunken monkey, thanks.

I tried something different and split that into 3 headings. What do you think?

Thanks for the suggestion! However, I’m not sure I’m convinced.
In theory, it seems like a good idea to separate the rules for the two, but then the extra “Acronyms in a Class or Method name” section makes it awkward. You now have to read two sections for the naming conventions of a specific entity instead of one, which might make it easier to miss. It also looks a bit silly to have a section with just a single sentence.
“Stand-alone name examples” being a sub-section of that also doesn’t make much sense, I guess it would make more sense to bump it up to an <h3>? Or maybe all four should be <h4> under a new <h3>Object-oriented code</h3> heading (or similar)? The first half of the example could even be nested under “Classes and Interfaces”, as it only lists those.

All in all, to me it seems like this creates more problems than it solves, tbh, if only because of the acronyms rule and the example code that is pertinent to both classes and methods. (Also, I guess the acronyms rule even applies to properties? Would be strange if it were XmlSource and getXml() but $extractedXML.)

I can't quite translate the last comment to actual changes. But since this is now going beyond a merge of one page into another I have reverted the split of the headings. I have changed the heading 'Classes' to "Classes, Methods and Properties" as suggested in #4. So let's go with that.

The examples that go along with this should be improved but should be a separate issue.