app/irc: update README & clarify gnutls dependency

modules/app/irc/README.org

@@ -7,8 +7,11 @@
 - [[#description][Description]]
   - [[#module-flags][Module Flags]]
   - [[#plugins][Plugins]]
-- [[#dependencies][Dependencies]]
 - [[#prerequisites][Prerequisites]]
+  - [[#macos][macOS]]
+  - [[#debian--ubuntu][Debian / Ubuntu]]
+  - [[#arch-linux][Arch Linux]]
+  - [[#nixos][NixOS]]
 - [[#features][Features]]
   - [[#an-irc-client-in-emacs][An IRC Client in Emacs]]
 - [[#configuration][Configuration]]
@@ -17,7 +20,7 @@
 - [[#troubleshooting][Troubleshooting]]
 
 * Description
-This module turns adds an IRC client to Emacs with OS notifications.
+This module turns Emacs into an IRC client, capable of OS notifications.
 
 ** Module Flags
 This module provides no flags.
@@ -26,11 +29,27 @@ This module provides no flags.
 + [[https://github.com/jorgenschaefer/circe][circe]]
 + [[https://github.com/eqyiel/circe-notifications][circe-notifications]]
 
-* Dependencies
-This module requires =gnutls-cli= or =openssl= for secure connections.
-
 * Prerequisites
-This module has no direct prerequisites.
+This module requires =gnutls= for secure IRC connections to work.
+
+** macOS
+#+BEGIN_SRC sh
+brew install gnutls
+#+END_SRC
+
+** Debian / Ubuntu
+#+BEGIN_SRC sh
+apt install gnutls-bin
+#+END_SRC
+
+** Arch Linux
+#+BEGIN_SRC sh
+pacman -S gnutls
+#+END_SRC
+** NixOS
+#+BEGIN_SRC nix
+environment.systemPackages = [ pkgs.gnutls ];
+#+END_SRC
 
 * Features
 ** An IRC Client in Emacs
@@ -54,20 +73,23 @@ When in a circe buffer these keybindings will be available.
 | ~circe-reconnect~           | =SPC m R= | Reconnect the current server                 |
 
 * Configuration
-Use ~set-irc-server!~ to configure IRC servers. Its second argument (a plist)
+Use ~set-irc-server! SERVER PLIST~ to configure IRC servers. Its second argument (a plist)
 takes the same arguments as ~circe-network-options~.
 
 #+BEGIN_SRC emacs-lisp :tangle no
-(set-irc-server! "chat.freenode.net"
+;; if you omit =:host=, ~SERVER~ will be used instead.
+(after! circe
+  (set-irc-server! "chat.freenode.net"
     `(:tls t
+      :port 6697
       :nick "doom"
       :sasl-username "myusername"
       :sasl-password "mypassword"
-    :channels ("#emacs")))
+      :channels ("#emacs"))))
 #+END_SRC
 
-*It is a obviously a bad idea to store auth-details in plaintext,* so here are
+However, *it is a obviously a bad idea to store your password in plaintext,* so
-some ways to avoid that:
+here are ways to avoid that:
 
 ** Pass: the unix password manager
 [[https://www.passwordstore.org/][Pass]] is my tool of choice. I use it to manage my passwords. If you activate the
@@ -80,6 +102,7 @@ password store.
 #+BEGIN_SRC emacs-lisp :tangle no
 (set-irc-server! "chat.freenode.net"
   `(:tls t
+    :port 6697
     :nick "doom"
     :sasl-username ,(+pass-get-user   "irc/freenode.net")
     :sasl-password ,(+pass-get-secret "irc/freenode.net")
@@ -105,10 +128,10 @@ Note that =+pass-get-user= tries to find your username by looking for the fields
 listed in =+pass-user-fields= (by default =login=, =user==, =username== and
 =email=)=). An example configuration looks like
 
-#+BEGIN_SRC txt :tangle no
+#+begin_example
 mysecretpassword
 username: myusername
-#+END_SRC
+#+end_example
 
 ** Emacs' auth-source API
 ~auth-source~ is built into Emacs. As suggested [[https://github.com/jorgenschaefer/circe/wiki/Configuration#safer-password-management][in the circe wiki]], you can store