When non-nil, `line-move' moves point by visual lines.
This movement is based on where the cursor is displayed on the
screen, instead of relying on buffer contents alone. It takes
into account variable-width characters and line continuation.
If nil, `line-move' moves point by logical lines.
A non-nil setting of `goal-column' overrides the value of this variable
and forces movement by logical lines.
A window that is horizontally scrolled also forces movement by logical lines.