[clang] [clang] Add the candiscard attribute to suppress nodiscard (PR #154943)

[Nikolas Klauser via cfe-commits]

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@@ -3646,6 +3646,14 @@ def Unavailable : InheritableAttr {
   let MeaningfulToClassTemplateDefinition = 1;
 }
 
+def CanDiscard : InheritableAttr {
+  let Spellings = [CXX11<"clang", "candiscard">,
+                   GCC<"candiscard">];
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philnik777 wrote:

I don't think so. This should probably be `Clang<"candiscard">` (or whatever the name will be in the end)

https://github.com/llvm/llvm-project/pull/154943