[removal] Replace ForbiddenNodeRule with dedicated ForbiddenTraitRule and ForbiddenSwitchRule

[TomasVotruba]

Why

ForbiddenNodeRule was a single configurable rule banning 8 node types (traits, switch, empty(), @ suppression, string interpolation, post inc/dec) under one shared identifier symplify.forbiddenNode. Two problems:

• No granular opt-out - all 8 bans share one identifier, so ignoreErrors cannot silence a single node type.
• Coarse toggle - symplify.configurable: false also kills unrelated configurable rules.

It also hid too much behind one opaque message with no reason or alternative.

What

• Remove ForbiddenNodeRule and its generic node list.
• Add dedicated ForbiddenTraitRule and ForbiddenSwitchRule, each with its own identifier (symplify.forbiddenTrait, symplify.forbiddenSwitch) and a message that names the alternative.
• Wire both into configurable-rules.neon (toggled by symplify.configurable) and rector-rules.neon.
• The other 6 node bans are dropped.

Checks

ECS, PHPStan, Rector and PHPUnit all green.

[staabm]

This PR immediately broke our builds on release, as its a BC break hidden in a minor release

[staabm]

the projects readme promotes use of single rules by documentation like

rules:
    - Symplify\PHPStanRules\Rules\CheckRequiredInterfaceInContractNamespaceRule

so I think removing rules should not happen in non-major releases

[TomasVotruba]

Let me patch it. Use the old tag for now.

How do you use it?

[staabm]

in the relevant case we are using a configurable rule like

        class: Symplify\PHPStanRules\Rules\ForbiddenNodeRule
        tags: [phpstan.rules.rule]
        arguments:
            forbiddenNodes:
                - PhpParser\Node\Expr\Exit_

thank you

[TomasVotruba]

Getting on subway, just a sec...

[TomasVotruba]

Fixed: #346

Taggec 14.18.1