Update ARIA-tech-src.xml

I understand what the author is getting at but 'there is no a priori knowledge' is better expressed as 'there is a posteriori knowledge'. Given that many developers have English as a second language, I don't think that the use of Latin is helpful.
Update ARIA-tech-src.xml

Updated after discussion with 'awkawk'
Merge pull request #9 from anormand/patch-1

Update ARIA-tech-src.xml