Add semicolon at the end of the line on code example

PiperOrigin-RevId: 530445615
Change-Id: I0c112773e7f42989840cb8b915167ade8833ef73

Author: Abseil Team

absl/status/statusor.h

@@ -146,7 +146,7 @@ class ABSL_MUST_USE_RESULT StatusOr;
 //
 //   absl::StatusOr<int> i = GetCount();
 //   if (i.ok()) {
-//     updated_total += *i
+//     updated_total += *i;
 //   }
 //
 // NOTE: using `absl::StatusOr<T>::value()` when no valid value is present will