Minor fixes in window handling code and docs.

Minor fixes in window handling code and docs.

* window.c (Vwindow_combination_resize)
(Vwindow_combination_limit): Use t instead of non-nil in
doc-strings.
* window.el (delete-other-windows): Use correct frame in call to
window-with-parameter.
* windows.texi (Splitting Windows): Use t instead of non-nil
when describing window-combination-resize.