[-Wunsafe-buffer-usage] Add a subgroup -Wunsafe-buffer-usage-in-container (#75665)

Add a sub diagnostic group under `-Wunsafe-buffer-usage` controlled by
`-Wunsafe-buffer-usage-in-container`. The subgroup will include warnings
on misuses of `std::span`, `std::vector`, and `std::array`.

Author: ziqingluo-90

clang/include/clang/Basic/DiagnosticGroups.td

@@ -1488,4 +1488,5 @@ def DXILValidation : DiagGroup<"dxil-validation">;
 def ReadOnlyPlacementChecks : DiagGroup<"read-only-types">;
 
 // Warnings and fixes to support the "safe buffers" programming model.
-def UnsafeBufferUsage : DiagGroup<"unsafe-buffer-usage">;
+def UnsafeBufferUsageInContainer : DiagGroup<"unsafe-buffer-usage-in-container">;
+def UnsafeBufferUsage : DiagGroup<"unsafe-buffer-usage", [UnsafeBufferUsageInContainer]>;