[clang] [clang][analyzer] Add "pedantic" mode to StreamChecker. (PR #87322)

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NagyDonat wrote:

I feel that "AssumeOftenUncheckedOperationsMayFail" does not provide more information than "Pedantic" (≈ report issues that are often left unchecked), while it is significantly longer, so my preferences are _Pedantic > AssumeSuccessfulWrites > AssumeOftenUncheckedOperationsMayFail_.

https://github.com/llvm/llvm-project/pull/87322