fix(terminal): use coladvance() to calculate buffer cursor position

src/nvim/cursor.c

@@ -108,6 +108,7 @@ static int coladvance2(pos_T *pos, bool addspaces, bool finetune, colnr_T wcol_a
   int head = 0;
 
   one_more = (State & INSERT)
+             || (State & TERM_FOCUS)
              || restart_edit != NUL
              || (VIsual_active && *p_sel != 'o')
              || ((ve_flags & VE_ONEMORE) && wcol < MAXCOL);