@param null | string and other spaced union types not parsed correctly

[mohsentm]

JsonMapper does not correctly parse PHPDoc union types when there are spaces around the pipe character (e.g., null | string or string | null). This results in Empty type errors when mapping data to properties, which is a common issue with autogenerated PHP models (such as those generated by OpenAPI Generator). The parser should normalize these annotations and handle spaced union types the same way it handles compact ones like string|null.

[SvenRtbg]

It's likely related to #242 which also incorrectly finds classes with the same start.