bug#55357: 29.0.50; [PATCH] Fix browse-url-emacs on file:// urls

[Eli Zaretskii]

> Resent-From: Yuan Fu <casouri@gmail.com>
> Original-Sender: "Debbugs-submit" <debbugs-submit-bounces@debbugs.gnu.org>
> Resent-CC: bug-gnu-emacs@gnu.org
> Resent-Sender: help-debbugs@gnu.org
> From: Yuan Fu <casouri@gmail.com>
> Date: Wed, 11 May 2022 00:05:50 -0700
> 
> 
> [1:text/plain Hide]
> 
> 
> If you call browse-url-emacs with a file:// url, Emacs does not open the 
> correct file:
> 
> (browse-url-emacs "file://~/a/b") opens /a/b
> (browse-url-emacs "file://a/b") opens /b
> 
> Basically unless the path is an absolute path, the first level is chopped 
> because url parses it as host and throws it away. This patch concats the host 
> back. If the path is absolute, host is empty string so it’s ok.

I think your URLs lack one or two more slashes.  See

  https://en.wikipedia.org/wiki/File_URI_scheme#How_many_slashes?