Avoid ambiguity about what st refers to

* lisp/term/st.el: Add link to website.

lisp/term/st.el

@@ -1,6 +1,14 @@
 ;;; st.el --- terminal initialization for st  -*- lexical-binding:t -*-
+
 ;; Copyright (C) 2020 Free Software Foundation, Inc.
 
+;;; Commentary:
+
+;; Support for the st terminal emulator.
+;; https://st.suckless.org/
+
+;;; Code:
+
 (require 'term/xterm)
 
 (defun terminal-init-st ()