Call this function to scroll the text of a multiple-line edit control.
This member function is processed only by multiple-line edit controls.
The edit control does not scroll vertically past the last line of text in the edit control. If the current line plus the number of lines specified by nLines exceeds the total number of lines in the edit control, the value is adjusted so that the last line of the edit control is scrolled to the top of the edit-control window.
LineScroll can be used to scroll horizontally past the last character of any line.
For more information, see EM_LINESCROLL in the Windows SDK.