bug#61919: Action key does not open Emacs mail msg files from shell

[John Cummings]

I use:  Editor:      GNU Emacs 28.2
        Hyperbole:   9.0.0
        Sys Type:    x86_64-pc-linux-gnu
        OS Type:     gnu/linux
        Window Sys:  None
        News Reader: Gnus v5.13
        Install:     elpa-devel, 8.0.1pre0.20230227.3018
(HyDebug) ButProps: (variable-documentation "The currently selected Hyperbole 
button.  Available to action routines." lbl-key "#*message*-20230220-192738#" 
lbl-start 11965 lbl-end 11992 categ ibtypes::pathname loc #<buffer *shell*> dir 
"/home/emacs/shellbug/examples/mail/" actype actypes::link-to-file args 
("#*message*-20230220-192738#"))

Given:
In a shell buffer, run an ls command in a directory containing a file
named like this Emacs-generated mail file (the quotes are not part of
the file name): '#*message*-20230220-192738#'

Expected behavior:
Hyperbole's smart keys will interpret this as a filename, and the
action key will open that file.

Actual behavior:
Hyperbole does seem to interpret it as a filename, but an error occurs
when hitting the action key, indicating it may not be determining the
file's location correctly. A portion of that error backtrace:

  Debugger entered--Lisp error: (error "(hpath:find): 
\"#*message*-20230220-192738#\" does n...")
    error("(hpath:find): \"%s\" does not exist" "#*message*-20230220-192738#")
    hpath:find("#*message*-20230220-192738#")
    actypes::link-to-file("#*message*-20230220-192738#")

Here is what hkey-help says about the name from the shell buffer:

  A press of the Action Key
  WHEN  (hbut:at-p)
  CALLS (hui:hbut-act) WHICH WILL:
  
    Execute action for optional Hyperbole button symbol BUT in current buffer.
    The default is the current button.
    
    (fn &optional BUT)
  
  pathname BUTTON SPECIFICS:
     lbl-key:         "#*message*-20230220-192738#"
     lbl-start:       11965
     lbl-end:         11992
     categ:           ibtypes::pathname
     loc:             #<buffer *shell*>
     dir:             "/home/emacs/shellbug/examples/mail/"
     actype:          link-to-file
     args:            ("#*message*-20230220-192738#")