[llvm] [ADT] Deprecate the redirection from SmallSet to SmallPtrSet (Take 2) (PR #155078)

[Jakub Kuderski via llvm-commits]

kuhar wrote:

> after this PR, i am seeing ~1800+ messages of the form llvm/include/llvm/ADT/SmallSet.h:280:43: warning: ‘template<class PointerType, unsigned int N> class llvm::DeprecatedSmallSet’ is deprecated: Use SmallPtrSet instead [-Wdeprecated-declarations]
> 
> was this expected ?

In llvm and its subprojects, or in a downstream project?

https://github.com/llvm/llvm-project/pull/155078