Tag Processor: Remove the shorthand next_tag( $tag_name ) syntax

[adamziel]

A part of #44410

What?

In @dmsnell's words:

My worry is that we say you can search for a given tag name, but then people want a short hand for class name, so we add it, but then if you don't specify a tag you have ->next( null, 'wp-block-group' ) everywhere. Or someone thinks, let's put class name first, and then we have the other problem.

I'd even be for exposing this shorthand only after we see use in practice to see if people even want it, and if so, which convention is more dominant.

Alternatively it's always easy to later add new specialized methods. Suppose we only expose ->next() right now, taking a query object. we can add ->next_tag( 'img' ) and ->next_with_class( 'wp-block-group' ). performance wise this is a "free" option

It resonates with me, so this PR removes the shorthand syntax and renames the long tag_name and class_name keys to short tag and class ones.

Before:

$p->next_tag( 'p' );

After:

$p->next( array( 'tag' => 'p' ) );

Testing Instructions

Confirm the CI passed and that no next_tag, tag_name, and class_name mentions were missed in this refactoring.

cc @dmsnell

[dmsnell]

Unfortunately there's already a branch named tag-processor so I can't checkout this branch as usual (because the tag name conflicts with the existing tag through the /).

If you also want to check it out locally, rename it.

git checkout -b update/tag-processor-cleanup-api origin/tag-processor/cleanup-api

[dmsnell]

the nesting catches my attention.

I don't think we need to change this code at all because we only set the query parameters if we have an array with the given keys. isset() is inherently safe to call.

it would be different if we did something to alert a dev of passing a non-array value, but right now there's no difference between passing a non-array and passing an array with the wrong keys.

[adamziel]

Well, good point! I just reverted this part

[adamziel]

Unfortunately there's already a branch named tag-processor so I can't checkout this branch as usual (because the tag name conflicts with the existing tag through the /).

If you also want to check it out locally, rename it.

git checkout -b update/tag-processor-cleanup-api origin/tag-processor/cleanup-api

Oops, sorry about that! Let's close this one and continue in #45082