Correct typo
found while addressing reviewer remarks for #88316
// arms whose patterns were composed solely of constants to not have
// them linked in the cfg.
//
-// THis was broken for various reasons. In particular, that hack was
+// This was broken for various reasons. In particular, that hack was
// originally authored under the assunption that other checks
// elsewhere would ensure that the two patterns did not overlap. But
// that assumption did not hold, at least not in the long run (namely,