[PATCH/DOC] Prec: add doc for record save and record record restore

[Eli Zaretskii]

> From: Hui Zhu <teawater@gmail.com>
> Date: Fri, 18 Jun 2010 11:21:01 +0800
> 
> I found that there is not doc for record save and record record
> restore.  Add this patch for this 2 commands.

Thanks.

> +Default filename is 'gdb_record.<process_id>'.

This needs the markup fixed and some explanations:

  Default filename is @file{gdb_record.@var{process_id}}, where
  @var{process_id} is the process ID of the @value{GDBN} process.

> +File must be created with @code{record save}.

"File must have been created with @code{record save}."

Okay with these changes.