NEWS and manual changes for command options changes

NEWS and manual changes for command options changes

gdb/ChangeLog:
2019-06-13  Pedro Alves  <palves@redhat.com>

	* NEWS (New commands): Mention "maint test-options
	require-delimiter", "maint test-options unknown-is-error", "maint
	test-options unknown-is-operand" and "maint show
	test-options-completion-result".
	(New command options, command completion): New section.
	(Completion improvements): New section.
	Mention that you can abbreviate "unlimited".

gdb/doc/ChangeLog:
2019-06-13  Pedro Alves  <palves@redhat.com>

	* gdb.texinfo (Command Completion): Mention command options too.
	(Command Options): New node.
	(Threads): Add anchors.  Extend descriptions of the "taas" and
	"tfaas" commands.
	(Backtrace): Describe new options of the "backtrace" command.  Add
	anchors.
	(Frame Apply): Describe new options of the "frame apply" and
	"faas" commands.  Add anchors.
	(Data): Describe new options of the "print" command.  Add anchors.
	(Compiling and Injecting Code): Mention options of the "compile
	print" command.
	(Maintenance Commands): Mention "maint test-options" subcommands
	and the "maint show test-options-completion-result" command.