Return the character position of the last character on the current line.
With argument N not nil or 1, move forward N - 1 lines first.
If scan reaches end of buffer, return that position.
This function ignores text display directionality; it returns the
position of the last character in logical order, i.e. the largest
character position on the line.
This function constrains the returned position to the current field
unless that would be on a different line than the original,
unconstrained result. If N is nil or 1, and a rear-sticky field ends
at point, the scan stops as soon as it starts. To ignore field
boundaries bind `inhibit-field-text-motion' to t.
This function does not move point. (fn &optional N)