PHPStan: don't treat PHPDoc as certain.

Can't ever really trust what plugins might be passing around, so while the PHPDoc needs to be accurate, the internals need to be able to perform sanity checks on parameter values without PHPStan complaining.

Author: JJJ

phpstan.neon.dist

@@ -1,5 +1,6 @@
 parameters:
     level: 6
+	treatPhpDocTypesAsCertain: false
     paths:
         - wp-multi-network/includes
         - wpmn-loader.php