* main.c (filename_completer): Don't complete to files ending in ~.

	* main.c (filename_completer): Don't complete to files ending in ~.

	* NEWS: Mention filename completion and "info line" enhancements.

	* main.c (symbol_completion_function): On "info t foo", return NULL,
	don't error().

	* main.c (symbol_completion_function): Don't use readline word
	breaking.  Use new calling convention for c->completer and
	complete_on_cmdlist.
	* command.h (struct command): Change arguments; now the text passed
	to completer does not have any word breaking done.  New arg word.
	* symtab.{c,h} (make_symbol_completion_list): Do word breaking.  Take
	word argument.
	* {main.c,gdbcmd.h} ({filename,noop}_completer): Take word argument.
	* command.{c,h} (complete_on_cmdlist): Take word argument.

	* command.c (lookup_cmd_1): Doc fix.