`-Wstring-concatenation` seems insufficiently alarmist

[r-barnes]

int main()
{
    // Or this one
    const char* v3[]  = {
        "One",
        "Two" 
        "Three",
        "Four",
        "Five",
        "Six"
        "Seven",
        "Eight",
        "Nine",
        "Ten",
        "Eleven",
    };      
}

does not raise a -Wstring-concatenation warning because two commas are missing (godbolt).

Perhaps a better heuristic for -Wstring-concatenation is "if strings on either side of me are delimited by commas, I should probably have one as well".

[r-barnes]

Left comments w.r.t. revert on #154018