Nullable types must be explicit

Added explicit nullable types to @docs.

Tested it and seems to not be giving issue anymore

The mentioned warnings were occuring because in PHP 8.4, the practice of allowing parameters to be null without explicitly declaring them as nullable has been deprecated. This means that if a function parameter has a default value of null, it must be explicitly marked as nullable using ?
The MR addresses the issue correctly and I have tested the MR and those are resolved now. hence moving the issue to RTBC.