Suppress a clang 12 warning about "suspicious concatenation".

My clang doesn't like it when we write code like this:

char *list[] = {
   "abc",
   "def",
   "ghi"
   "jkl"
}

It wonders whether we meant to put a comma between "ghi" and "jkl" or not, and gives a warning.

To suppress this warning (since in this case, we did mean to omit the comma), we just wrap the two strings in parentheses.

Closes #40426 (closed); bugfix on 0.4.0.4-rc.