Issue #3426548 follow-up: Convert the PHPStan baseline from NEON to PHP

*.xml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2

*.yml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2

# PHPStan's baseline uses tabs instead of spaces.

core/.phpstan-baseline.php text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tabwidth=2 diff=php linguist-language=php

# Define binary file attributes.

# - Do not treat them as text.

# - Include binary diff in patches instead of "binary files differ."