Bug fixes

[2ae68917] Fix full width datetime input (single widget) (@Seb33300) [9ec576c1] Fix Fieldset header styles (@kteterycz) [e14e0af1] Fix nullable detection (@DrWarpMan) [58b81583] Update Italian translations (@gremo) [2b14df46] Fix a deprecation related to Symfony 7.1 (@javiereguiluz) [1fcf7e87][19c647d4][1ddf3c42] Misc. doc fixes (@Chris53897, Rémi Fongaufier, @Romaixn)