meta should only be collected between the userstyles headers

[isabelroses]

When using the @name outside of the userstyles headers, the package would still detect that and set it to the name of the userstyle.

In the example below, the @name is used and when collecting the metadata. the name of the userstyle is set to ) {
https://github.com/catppuccin/userstyles/blob/main/styles/chess.com/catppuccin.user.css#L64-L66

[eight04]

This library was designed to parse metadata block only. I won't mind if we try to stop parsing when getting a ==/UserStyle== though.