[11.x] Improve PHPDoc for `mapSpread` Method in `Arr` Class & Remove Warning from IDE #39114

Job	Run time
PHP 8.2 - PHPUnit 10.5 - prefer-lowest	2m 25s
PHP 8.2 - PHPUnit 10.5 - prefer-lowest - Windows	2m 23s
PHP 8.2 - PHPUnit 10.5 - prefer-stable	2m 23s
PHP 8.2 - PHPUnit 10.5 - prefer-stable - Windows	2m 21s
PHP 8.2 - PHPUnit 11.0.1 - prefer-lowest - Windows	2m 19s
PHP 8.2 - PHPUnit 11.0.1 - prefer-lowest	2m 27s
PHP 8.2 - PHPUnit 11.0.1 - prefer-stable - Windows	2m 23s
PHP 8.2 - PHPUnit 11.0.1 - prefer-stable	2m 26s
PHP 8.3 - PHPUnit 10.5 - prefer-lowest - Windows	2m 26s
PHP 8.3 - PHPUnit 10.5 - prefer-lowest	2m 28s
PHP 8.3 - PHPUnit 10.5 - prefer-stable	2m 14s
PHP 8.3 - PHPUnit 10.5 - prefer-stable - Windows	2m 30s
PHP 8.3 - PHPUnit 11.0.1 - prefer-lowest	2m 57s
PHP 8.3 - PHPUnit 11.0.1 - prefer-lowest - Windows	2m 24s
PHP 8.3 - PHPUnit 11.0.1 - prefer-stable	2m 20s
PHP 8.3 - PHPUnit 11.0.1 - prefer-stable - Windows	2m 21s
	38m 47s

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