update description for open_github (#83)

* update desc for open_github

update description for open_github after extending its functionality to be able to open PRs directly from the command line

* Update open_github

packages/open_github

 type = plugin
 repository = https://github.com/patrickf3139/open_github
 maintainer = patrickf3139
-description = Shortcut to open the GitHub page for the current branch in browser
+description = Jump to the GitHub PR page or tree view for the current branch
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