Revert "Updated ver info to 3.1 & codename to Ascraeus"

This reverts commit ae7775a291814c0c7a5d7a149b231a00eecccab3.
Add extension to glossary for phpBB 3 1
Merge branch 'add-ext-to-glossary-3-1' of https://github.com/Danielx64/documentation into add-ext-to-glossary-3-1

Conflicts:
	documentation/content/en/chapters/glossary.xml
Added the word extension to the glossary since it's a part of phpBB 3.1