Release v6.4.0 - A high-energy explosion

What's Changed

• Add @phpstan-return never by @IanDelMar in #110
• Add support for placing string literals into PHPStan types by @johnbillion in #111
• Fix type in variable docblock by @IanDelMar in #113
• Use visitor to add @phpstan-return void by @IanDelMar in #121
• functionMap: additions, improvement, corrections by @IanDelMar in #127
• Delete wp_clear_scheduled_hook.php by @IanDelMar in #129
• Remove wp_clear_scheduled_hook from TypeInferenceTest by @IanDelMar in #130
• Remove get_objects_in_term() from functionMap by @IanDelMar in #131

Full Changelog: v6.3.2...v6.4.0