Add usage information for terminal

modules/terminal/init.zsh

@@ -5,6 +5,12 @@
 #   James Cox <james@imaj.es>
 #   Sorin Ionescu <sorin.ionescu@gmail.com>
 #
+# Usage:
+#   To auto set the terminal window and tab titles with the current command or
+#   directory, add the following to zshrc:
+#
+#     zstyle ':omz:module:terminal' auto-title 'yes'
+#
 
 # Dumb terminals lack support.
 if [[ "$TERM" == 'dumb' ]]; then