This check aims to determine values and references that could be declared
as const, but are not.
The first version I am aiming at only analyzes local variables.
No fixits are emitted.
This check aims to implement CPPCG-ES. 25: Declare an object const or constexpr unless you want to modify its value later on
and HICPP-7.1.2 Use const whenever possible.
Because const-correctness includes many issues this check will be implemented
in multiple stages.