patch 8.2.3234: crash when printing long string with Lua

Problem:    Crash when printing long string with Lua.
Solution:   Remove lua_pop(). (Martin Tournoij, closes #8648)
diff --git a/src/if_lua.c b/src/if_lua.c
index 82dffb0..79fb681 100644
--- a/src/if_lua.c
+++ b/src/if_lua.c
@@ -1734,9 +1734,9 @@
 	s = lua_tolstring(L, -1, &l);
 	if (s == NULL)
 	    return luaL_error(L, "cannot convert to string");
-	if (i > 1) luaL_addchar(&b, ' '); // use space instead of tab
+	if (i > 1)
+	    luaL_addchar(&b, ' '); // use space instead of tab
 	luaV_addlstring(&b, s, l, 0);
-	lua_pop(L, 1);
     }
     luaL_pushresult(&b);
     if (!got_int)