docs bug: add systemctl --user start lorri.socket to set-up steps

[n-hebert]

Describe the bug
As mentioned in #72, the set-up steps are simply missing the line systemctl --user start lorri.socket after the daemon-reload.
I couldn't get lorri working, and then found #72 and followed the one step and - boom - works great.

To Reproduce
Steps to reproduce the behavior:

1. Follow the readme

Expected behavior

Lorri works

Metadata
n/a

Additional context
I'm not sure why #72's excellent idea was declined an implementation but this is an easy solution to ensure everyone gets working.
A reboot is overkill when you just need to start the socket.

I can provide the PR, if desired! 🚀

[n-hebert]

Example patch. I can open a PR if agreeable.

From 5bd8940795aab2ef205cfbd6ec003668eae63f4a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicholas=20H=C3=A9bert?=
 <[email protected]>
Date: Tue, 9 Apr 2024 09:48:47 -0300
Subject: [PATCH] Add socket guidance

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 3e8c435..9a05bcb 100644
--- a/README.md
+++ b/README.md
@@ -50,7 +50,7 @@ platforms](#setup-on-other-platforms).
    **Note**: There's [a known issue](https://github.com/target/lorri/issues/374 "nixpkgs `services.lorri` requires reboot for the user lorri.socket to appear")
    preventing the lorri daemon from starting automatically upon installation.
    Until it's resolved, you'll have to reload the user daemon by hand by
-   running `systemctl --user daemon-reload`, or reboot.
+   running `systemctl --user daemon-reload && systemctl --user start lorri.socket`, or reboot.
 
 2. **Install direnv.** Add `pkgs.direnv` to `environment.systemPackages` in
    your NixOS `configuration.nix` or to `home.packages` in your home-manager
-- 
2.42.0