Clean up doc

plugins/jira/jira.plugin.zsh

-# To use: add a .jira-url file containing your 
-# Jira project's base url in the root of your project.
-# Example: https://name.jira.com
+# To use: add a .jira-url file in the base of your project
+# Setup: cd to/my/project
+         echo "https://name.jira.com" >> .jira-url
 # Usage: jira           # opens a new issue
 #        jira ABC-123   # Opens an existing issue
 open_jira_issue () {