Tweak wording of new icon credit

Author: gjsjohnmurray

README.md

@@ -180,4 +180,4 @@ To obtain an array of server names:
 For details of the API, including result types and available parameters, review the source code of the extension's `activate` method [here](https://github.com/intersystems-community/intersystems-servermanager/blob/master/src/extension.ts).
 
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-<div>Icons made by <a href="https://www.freepik.com" title="Freepik">Freepik</a> from <a href="https://www.flaticon.com/" title="Flaticon">www.flaticon.com</a></div>
+<div>Activity Bar icon made by <a href="https://www.freepik.com" title="Freepik">Freepik</a> from <a href="https://www.flaticon.com/" title="Flaticon">www.flaticon.com</a></div>