Clean up comments in pj plugin file and reorganise

plugins/pj/pj.plugin.zsh

-#!/bin/zsh
-
-#
-# Original idea by DefV (Jan De Poorter)
-# Source: https://gist.github.com/pjaspers/368394#comment-1016
-#
-# Usage:
-#  - Set `$PROJECT_PATHS` in your ~/.zshrc
-#    e.g.: PROJECT_PATHS=(~/src ~/work)
-#  - In ZSH you now can open a project directory with the command: `pj my-project`
-#    the plugin will locate the `my-project` directory in one of the $PROJECT_PATHS
-#    Also tab completion is supported.
-#  - `pjo my-project` will open the directory in $EDITOR
-# 
+alias pjo="pj open"
 
-function pj() {
+function pj () {
     cmd="cd"
     file=$1
 
@@ -36,8 +23,6 @@ function pj() {
     echo "No such project $1"
 }
 
-alias pjo="pj open"
-
 function _pj () {
     # might be possible to improve this using glob, without the basename trick
     typeset -a projects
@@ -45,5 +30,4 @@ function _pj () {
     projects=$projects:t
     _arguments "*:file:($projects)"
 }
-
 compdef _pj pj