* doc/lispref/buffers.texi (Read Only Buffers): Describe optional
argument POSITION.
* doc/lispref/debugging.texi (Error Debugging): `debug-on-signal'
is an option.
* doc/lispref/display.texi (Refresh Screen): Describe optional
argument FRAME of `redraw-frame'.
(Attribute Functions): Describe optional argument CHARACTER of
`face-font'.
(Defining Images): `image-load-path' is an option.
(Beeping): `ring-bell-function' is an option.
* doc/lispref/frames.texi (Size and Position): The PIXELWISE
argument of `set-frame-size' is optional.
(Raising and Lowering): The TERMINAL argument of `tty-top-frame'
is optional.
* doc/lispref/keymaps.texi (Controlling Active Maps): Fix doc of
`set-transient-map'.
* doc/lispref/minibuf.texi (Text from Minibuffer):
`read-regexp-defaults-function' is an option.
(Minibuffer Contents): `delete-minibuffer-contents' is a command.
* doc/lispref/modes.texi (Mode Line Variables):
`mode-line-position' and `mode-line-modes' are variables, not
options.
* doc/lispref/strings.texi (Creating Strings): The START argument
of `substring' is optional.
* doc/lispref/text.texi (Buffer Contents): Describe optional
argument NO-PROPERTIES of `thing-at-point'.
(User-Level Deletion): Both arguments of
`delete-trailing-whitespace' are optional.
(Margins): Use @key{RET} instead of @kbd{RET}.
* doc/lispref/windows.texi (Display Action Functions): Write
non-@code{nil} instead of non-nil.
(Choosing Window Options): The WINDOW arg of
`split-window-sensibly' is optional.
(Choosing Window Options): Write non-@code{nil} instead of
non-nil.
(Window Start and End): Both args of `window-group-end' are
optional.
* src/buffer.c (Fbarf_if_buffer_read_only): Rename argument POS
to POSITION to keep consisteny with doc-string.