[clang] [Clang] Add thousands-separator to "cannot allocate array; evaluated array bound [...] exceeds the limit" diagnostic (PR #211785)

[Ambrose Leeb via cfe-commits]

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@@ -1429,19 +1429,33 @@ inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
   return DB;
 }
 
+inline constexpr uint64_t DiagnosticIntegerSeparatorThreshold = 100'000;
+
+inline std::string formatDiagnosticInteger(const llvm::APInt &Val,
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Sirraide wrote:

I feel like the implementation of this should go in a `.cpp` file as it’s getting a bit long

https://github.com/llvm/llvm-project/pull/211785