Add U+26CC6 ()

(https://dict.variants.moe.edu.tw/dictView.jsp?ID=68560) 《異體字字典》uses U+26CC6 () as the standard form, while U+8412(萒) is a variant form. According to unicode 15.1, uni8412-TW (萒) was removed in 2.005, however this shape should be reused.