vim-patch:9.0.1330: handling new value of an option has a long "else if" chain

Problem:    Handling new value of an option has a long "else if" chain.
Solution:   Use a function pointer. (Yegappan Lakshmanan, closes vim/vim#12015)

af93691b53

src/nvim/lua/spell.c

@@ -39,7 +39,7 @@ int nlua_spell_check(lua_State *lstate)
   const int wo_spell_save = curwin->w_p_spell;
 
   if (!curwin->w_p_spell) {
-    did_set_spelllang(curwin);
+    parse_spelllang(curwin);
     curwin->w_p_spell = true;
   }