Support for type alias tags

[jiripudil]

This PR adds support for @psalm-type and @psalm-import-type as well as @phpstan- prefixed alternatives:

/**
 * @phpstan-type TypeAlias callable(string): bool
 */
class Foo {}

/**
 * @phpstan-import-type TypeAlias from Foo as ImportedAlias
 */
class Bar {}

[ondrejmirtes]

This is perfect! Thank you.