Industry bellwethers Walmart IncWMT.N and Target CorpTGT.N issued gloomy holiday sales forecasts last week, with Target pointing to a sharp fall in demand for discretionary goods. Adds details on results, background Nov 22 (Reuters) - Dollar Tree Inc DLTR.O said on Thursday that its full-year profit would be at the lower end of its forecast, with the discount store retailer's margins under pressure from decades-high inflation. Dollar Tree has been hit by slowing demand for everything from toys and party supplies to homeware, which are typically more profitable than food and other perishables.