Collate list of Third Party Open Source software #834

Changes done regarding  Collate list of Third Party Open Source software #834
the link on the previous line doesn't navigate directly to the Acknowledgements section. Here is the correct way to support it:
````
/org.mwc.debrief.help/html/legacy/index.html%23acknowledgements
````
(the case of acknowledgements has been changed, and the hash character replaced - the case of the "a" was my problem - sorry).