Clutter the code with "fall-through" comments in order to suppress nuisance

compiler warnings.  No logic changes.

FossilOrigin-Name: 05d2cf5e90d2a6b8e7fbcdb9e12e7c1281db7cfbe212997bd63c8aa66797edda

src/json.c

@@ -1911,6 +1911,7 @@ json_parse_restart:
       return i+4;
     }
     /* fall-through into the default case that checks for NaN */
+    /* no break */ deliberate_fall_through
   }
   default: {
     u32 k;