This fixes a similar issue with 'remove_substring' in both STRING_32 and STRING_8

         remove_substring (start_index, end_index: INTEGER)
			-- Remove all characters from `start_index'
			-- to `end_index' inclusive.
		local
			l_count, nb_removed: INTEGER
		do
			nb_removed := end_index - start_index + 1
			if nb_removed > 0 then
				l_count := count
				area.overlapping_move (start_index + nb_removed - 1, start_index - 1, l_count - end_index + 1)
				area.remove_tail (nb_removed)
				count := l_count - nb_removed
				reset_hash_codes
			end
		end