Form: getHttpData() return type reflects the $htmlName argument

[jaroslavlibal]

• bug fix getHttpData() PHPDoc typing values as string[], but the actual data can contain nested arrays #351
• BC break? no
• doc PR: —

The @return of Form::getHttpData() is not correct.

It says string|string[]|Nette\Http\FileUpload|null, but this only describes the call with a control name. There are two problems:

1. When called without arguments, the method returns all form data. This is a nested array (the whole POST tree), not string[]. So PHPStan thinks the result is string[] and reports errors on nested access like $data['x']['y'].

2. For one control, string[] is also not enough. A multi-file upload returns FileUpload[], not only string[].

This PR changes only the docblock to a conditional return type based on $htmlName:

@return ($htmlName is null ? mixed[] : string|string[]|Nette\Http\FileUpload|Nette\Http\FileUpload[]|null)

This probably replaces the older #333.

[dg]

Thanks, merged