bug#64546: 30.0.50; [PATCH] Add support for explicitly-remote commands in Eshell

[Jim Porter]

This patch adds the ability to run a command in Eshell from any host, no 
matter your current directory. For example, you could run 
"/ssh:user@remote:whoami" from a local dir, which would run "whoami" 
over the SSH connection for "user@remote". Similarly, you could run 
"/:whoami" to run the local "whoami" even from a remote dir. (The latter 
syntax is just piggybacking off of quoted file names, which otherwise 
have no special meaning in Eshell.)

Prior to the main patch, I also added a bit of documentation about how 
remote access works in Eshell. These are separate commits so that, if we 
wanted, we could backport the first patch to the Emacs 29 branch.

0001-Add-documentation-about-remote-access-in-Eshell.patch
Description: Text document

0002-Add-support-for-explicitly-remote-commands-in-Eshell.patch
Description: Text document