Fix obviously wrong class name references (#36769)

Almost all are phpdoc comments where the class was missing a `use` or
leading `\`. More specifically, I searched for cases where Phan was
complaining about classes named like `\Automattic\...\Automattic\`, or
`\WP_...`, or `Exception` classes, and fixed all the obvious ones.

Then I also searched for "undeclared {class|type} \[a-z]" and fixed the
obvious ones out of that too (e.g. "obj", "number", and various typos).

Note that having the correct typing allows Phan to complain about
possibly-real issues in some cases. Those will have to be reviewed
later.

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/8596601938

vendor/composer/installed.json

@@ -2,12 +2,12 @@
     "packages": [
         {
             "name": "automattic/jetpack-device-detection",
-            "version": "2.1.3-alpha.1712265966",
-            "version_normalized": "2.1.3.0-alpha1712265966",
+            "version": "2.1.3-alpha.1712563319",
+            "version_normalized": "2.1.3.0-alpha1712563319",
             "dist": {
                 "type": "path",
                 "url": "/tmp/jetpack-build/Automattic/jetpack-device-detection",
-                "reference": "69f6d2a5495e2c609d6c9523de438b49cc18021c"
+                "reference": "a9b7de14c343d0351f22ffce79d397bc5987e039"
             },
             "require": {
                 "php": ">=7.0"

vendor/composer/installed.php

@@ -11,9 +11,9 @@
     ),
     'versions' => array(
         'automattic/jetpack-device-detection' => array(
-            'pretty_version' => '2.1.3-alpha.1712265966',
-            'version' => '2.1.3.0-alpha1712265966',
-            'reference' => '69f6d2a5495e2c609d6c9523de438b49cc18021c',
+            'pretty_version' => '2.1.3-alpha.1712563319',
+            'version' => '2.1.3.0-alpha1712563319',
+            'reference' => 'a9b7de14c343d0351f22ffce79d397bc5987e039',
             'type' => 'jetpack-library',
             'install_path' => __DIR__ . '/../automattic/jetpack-device-detection',
             'aliases' => array(),