Function: set-window-text-height

Set the height in lines of the text display area of WINDOW to HEIGHT.
WINDOW must be a live window and defaults to the selected one.
HEIGHT doesn't include the mode line or header line, if any, or
any partial-height lines in the text display area.

Note that the current implementation of this function cannot
always set the height exactly, but attempts to be conservative,
by allocating more lines than are actually needed in the case
where some error may be present.