A few of my highlights/to be aware of:
* Add nullptr constant for nullptr_t type
* Add true and false keywords
* Add ' digit separator to literal constants, such as 0xFE'DC'BA'98
* The meaning of the auto keyword was changed to cause type inference while also retaining its old meaning of a storage class specifier if used alongside a type. Unlike C++, C23 allows type inference only for object definitions (no inferring function return type or function parameter type).
* Add char8_t type for storing UTF-8 encoded data and change the type of u8 character constants and string literals to char8_t
