[RFA] Improve help set/unset/show substitute-path

[Eli Zaretskii]

> Date: Fri, 12 Jan 2007 11:13:23 +0400
> From: Joel Brobecker <brobecker@adacore.com>
> 
> As promised to Daniel, hopefully the following patch will make the help
> text of the vaious substitute-path commands a bit better. Anyone either
> wanting to refresh his memory about the usage should now be able to
> use the help text for that. It's also easier to use the command without
> having read the documentation.

Thanks!

> +set substitute-path FROM TO\n\

I think it is better to say "Usage: set substitute-path FROM TO".

> +Add a source path substitution rule replacing FROM into TO in source paths.\n\

GNU standards dislike such usage of the word ``path''.  We should use
``file name'' instead.  (``Path'' is reserved for lists of directories,
such the values of $PATH and $MANPATH environment variables.)

> +unset substitute-path [FROM]\n\
> +If a path is specified (FROM), delete the associated rule from the current\n\
> +list of substitution rules.  A warning is emmitted by the debugger if\n\
> +no rule could be found.\n\
> +If no path is specified, then all substitution rules are deleted."),

I suggest to say this instead:

  Delete the rule for substituting FROM in source file names.  If FROM
  is not specified, all substituting rules are deleted.
  If the debugger cannot find a rule for FROM, it will display a
  warning.

> +show substitute-path [FROM]\n\
> +If a path is specified (FROM), print the source path substitution rule which\n\

Same here.