patch 8.1.1833: allocating a bit too much when there is no bad word.

Problem:    Allocating a bit too much when spellbadword() does not find a bad
            word.
Solution:   Reset "len" when going to the next word. (Daniel Hahler,
            closes #4788)

src/evalfunc.c

@@ -10755,6 +10755,7 @@ f_spellbadword(typval_T *argvars UNUSED, typval_T *rettv)
 		}
 		str += len;
 		capcol -= len;
+		len = 0;
 	    }
 	}
     }

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1833,
 /**/
     1832,
 /**/