feat: lay out long attributes as PER-CS 12.3 describes

[mreiden]

Problem

A long attribute is printed like an array, breaking the #[...] block before the attribute name and indenting the whole attribute:

#[
    AsCommand(
        name: 'app:insertions:autorenew',
        description: 'Automatically applies a new IO for carriers with an IO marked auto-renew',
    ),
]
class ApplyAutoRenewInsertionCommand extends Command

PER-CS 12.3 says:

If an attribute's argument list is split into multiple lines for any reason, then: the attribute MUST be the only one in its attribute block. The attribute arguments MUST follow the same rules as defined for multiline function calls.

with the example in 12.4:

#[Complex(
    prop: 'val',
    other: 5,
)]

This is also the form Symfony, Doctrine and PhpStorm produce, so the current output fights every other tool in a project.

Change

printAttrGroup():

• A block with one attribute is ["#[", attr, "]"], so only the argument list can break — #[AsCommand( … )].

• A block with several attributes stays on one line while it fits (#[Other, Stuff]); otherwise it becomes one block per attribute (#[A] #[B] is the same declaration as #[A, B]), which is what 12.3 requires and gives the familiar one-per-line Doctrine layout:

  #[ORM\Id]
  #[ORM\GeneratedValue(strategy: "CUSTOM")]
  #[ORM\CustomIdGenerator(class: SomeVeryLongGeneratorClassName::class)]

• Inline attributes (parameters, closures, anonymous classes) keep the existing newline after ] when they break, which puts a parameter's attribute on its own line before the parameter as 12.2 requires.

clean() flattens a node's attribute groups so AST_COMPARE=1 treats the split blocks as equivalent.

This is a formatting change: two existing snapshots (attributes, attributes-trail-comma) change from the array-like layout to the PER-CS one. The trailing comma from #1885 now lives inside the argument list, where printArgumentsList already puts it.

Tests

New tests/attributes/attributes-per-cs.php covers a long single attribute on a class, property, method, enum case and constant; a multi-attribute block that fits and one that splits; attributes on parameters in a multiline list, on closures and on an anonymous class. Full suite passes with AST_COMPARE=1; the output is idempotent and passes php -l.

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