Some minor fixes of Elisp manual.

Some minor fixes of Elisp manual.

* commands.texi (Recursive Editing): recursive-edit is a
command.
* compile.texi (Docs and Compilation):
byte-compile-dynamic-docstrings is an option.
* debugging.texi (Invoking the Debugger): debug is a command.
* display.texi (Progress): progress-reporter-update and
progress-reporter-force-update have VALUE argument optional.
(Animated Images): Use non-@code{nil} instead of non-nil.
* files.texi (Format Conversion Round-Trip): Use non-@code{nil}
instead of non-nil.
* frames.texi (Creating Frames): make-frame is a command.
(Input Focus): select-frame is a command.
(Pointer Shape): void-text-area-pointer is an option.
* help.texi (Describing Characters): read-kbd-macro is a
command.
(Help Functions): describe-prefix-bindings is a command.
* markers.texi (Creating Markers): Both arguments of copy-marker
are optional.
* minibuf.texi (Reading File Names): Use @kbd instead of @code.
* modes.texi (Mode Line Variables): mode-line-remote and
mode-line-client are not options.
(Imenu): imenu-add-to-menubar is a command.
(SMIE Indentation Helpers): Use non-@code{nil} instead of
non-nil.
* os.texi (Sound Output): play-sound-file is a command.
* package.texi (Package Archives): Use @key{RET} instead of
@kbd{RET}.
* processes.texi (Signals to Processes): Use @key{RET} instead
of @code{RET}.
(Signals to Processes): signal-process is a command.
* text.texi (Clickable Text): Use @key{RET} instead of
@kbd{RET}.
(Base 64): base64-encode-string is not a command while
base64-decode-region is.
* windows.texi (Switching Buffers): pop-to-buffer is a command.