[clang] [Clang] update reasoned delete diagnostic kind to use Extension, making it pedantic only (PR #114713)

[Aaron Ballman via cfe-commits]

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@@ -464,6 +464,8 @@ Improvements to Clang's diagnostics
 
 - Clang now diagnoses ``[[deprecated]]`` attribute usage on local variables (#GH90073).
 
+- Clang now diagnoses misused reasoned ``delete("reason")`` warnings only in pedantic mode. (#GH109311).
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AaronBallman wrote:

At this point, I'd prefer if you'd obtain commit privileges and land the changes yourself -- you have a number of patches under your belt, and it's better for folks to land their own changes in case of needing reverts, etc.

If there's a reason you don't want/can't get commit rights, feel free to let me know privately or otherwise, and I can certainly land the changes for you.

https://github.com/llvm/llvm-project/pull/114713