patch 8.2.0932: missspelling spelllang

Problem:    Missspelling spelllang.
Solution:   Add an "l". (Dominique Pelle)
diff --git a/src/optionstr.c b/src/optionstr.c
index ddb6c50..6071f46 100644
--- a/src/optionstr.c
+++ b/src/optionstr.c
@@ -1704,7 +1704,7 @@
 	int	is_spellfile = varp == &(curwin->w_s->b_p_spf);
 
 	if ((is_spellfile && !valid_spellfile(*varp))
-	    || (!is_spellfile && !valid_spellang(*varp)))
+	    || (!is_spellfile && !valid_spelllang(*varp)))
 	    errmsg = e_invarg;
 	else
 	    errmsg = did_set_spell_option(is_spellfile);