Upgraded code to use vimeo/psalm:^6 and infection/infection:0.29.10

To do this, we introduced `azjezz/psl` in the test suite, since life is too short to follow PHP-SRC's function
falsyess bullshit.

Also, various suppressions are now gone, since Psalm and Infection removed various deprecations and
mutable expressions.

The `psalm/plugin-phpunit` was also installed, so Psalm does no longer mark test classes as unused code.

composer.json

@@ -13,15 +13,17 @@
         "bin/roave-infection-static-analysis-plugin"
     ],
     "require": {
-        "php": "~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0",
+        "php": "~8.2.0 || ~8.3.0 || ~8.4.0",
         "composer-runtime-api": "^2.2",
-        "infection/infection": "^0.27.11 || ^0.28.0 || ^0.29.0",
+        "infection/infection": "0.29.10",
         "sanmai/later": "^0.1.4",
-        "vimeo/psalm": "^4.30.0 || ^5.15 || ^6.0"
+        "vimeo/psalm": "^5.15 || ^6.0"
     },
     "require-dev": {
+        "azjezz/psl": "^3.2",
         "doctrine/coding-standard": "^12.0.0",
-        "phpunit/phpunit": "^10.5.15"
+        "phpunit/phpunit": "^10.5.15",
+        "psalm/plugin-phpunit": "^0.19.2"
     },
     "autoload": {
         "psr-4": {
@@ -39,7 +41,7 @@
             "infection/extension-installer": false
         },
         "platform": {
-            "php": "8.1.99"
+            "php": "8.2.99"
         },
         "sort-packages": true
     }