Add direct link to github ribbon plugin

The former documentation referenced a plugin but left no easy way to
link to it. Also, the misleading text claiming a title also confused me.
I had to do some creative greping the git files to hunt it down.

Adding a TiddlyWiki link around the plugin links to the actual tiddler
that a reader could easily copy. This also deprecated the need for the
misleading title.

editions/tw5.com/tiddlers/howtos/How to put the last modification date in a banner.tid

@@ -6,7 +6,7 @@ type: text/vnd.tiddlywiki
 
 Here's how to display the last modification date of a wiki in a banner in the corner of the window:
 
-# Copy the plugin $:/plugins/tiddlywiki/github-fork-ribbon (labelled "GitHub-style ribbon in pure CSS") to your TiddlyWiki
+# Copy the plugin [[$:/plugins/tiddlywiki/github-fork-ribbon]] to your TiddlyWiki
 # Save and reload your wiki
 # Create a new tiddler called [[$:/_MyRibbon]] tagged [[$:/tags/PageControls]] and containing:<div>