[Analyzer][StdLibraryFunctionsChecker] Describe arg constraints

In this patch, I provide a detailed explanation for each argument
constraint. This explanation is added in an extra 'note' tag, which is
displayed alongside the warning.
Since these new notes describe clearly the constraint, there is no need
to provide the number of the argument (e.g. 'Arg3') within the warning.
However, I decided to keep the name of the constraint in the warning (but
this could be a subject of discussion) in order to be able to identify
the different kind of constraint violations easily in a bug database
(e.g. CodeChecker).

Differential Revision: https://reviews.llvm.org/D101060