Fix off-by-one error in Compiler Warnings by compiler version

[Rageking8]

To suppress warnings in the target version and all later versions, the version specified in /Wv must be the next older one.

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[Court72]

@TylerMSFT

Can you review the proposed changes?

Important: When the changes are ready for publication, adding a #sign-off comment is the best way to signal that the PR is ready for the review team to merge.

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[TylerMSFT]

@Rageking8, it's Monday; help me out with your thinking here :-)
If a warning is introduced in compiler version 19.43, wouldn't you suppress that warning for 19.43 with /Wv:19.43? I'm wondering why you went a version earlier because we don't want to suppress the warnings in the previous version of the compiler, but 'this' one.

[Rageking8]

In https://learn.microsoft.com/en-us/cpp/build/reference/compiler-option-warning-level?view=msvc-170 under /Wv:

Displays only warnings introduced in the version compiler version and earlier.

So for warnings introduced in 19.43, if you put the version as 19.43, those warnings will still show, with warnings introduced in 19.44 and later silenced.

Hopefully I interpreted that right, and all subsequent ones follow that pattern of 1 version older.

[TylerMSFT]

I think you are right. Good catch!

[TylerMSFT]

Thank you for fixing this sneaky error.

[TylerMSFT]

#sign-off

[Rageking8]

I think you are right. Good catch!

Took me some time to work out which was right as well. Might be due to the "whitelist" nature of the flag /Wv instead of what I would consider more intuitive at first, "blacklist".