backwardChars
Moves @count characters backward, if possible.
If @count would move past the start or end of the buffer, moves to the start or end of the buffer.
The return value indicates whether the iterator moved onto a dereferenceable position; if the iterator didn’t move, or moved onto the end iterator, then false is returned. If @count is 0, the function does nothing and returns false.
Return
whether @iter moved and is dereferenceable
Parameters
count
number of characters to move