vim-patch:8.1.0199: spellbadword() does not check for caps error

Problem:    spellbadword() does not check for caps error. (Dominique Pelle)
Solution:   Adjust capcol when advancing.
66ab916935

src/nvim/eval.c

@@ -16763,6 +16763,7 @@ static void f_spellbadword(typval_T *argvars, typval_T *rettv, FunPtr fptr)
           break;
         }
         str += len;
+        capcol -= len;
       }
     }
   }