string.c: term fill

* string.c (rb_str_justify): fill wchar terminator.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48778 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

string.c

@@ -7820,7 +7820,7 @@ rb_str_justify(int argc, VALUE *argv, VALUE str, char jflag)
            p += rlen2;
 	}
     }
-    *p = '\0';
+    TERM_FILL(p, rb_enc_mbminlen(enc));
     STR_SET_LEN(res, p-RSTRING_PTR(res));
     OBJ_INFECT(res, str);
     if (!NIL_P(pad)) OBJ_INFECT(res, pad);