Hi. Sorry, we are not able to merge pull requests for translation files. We are using an external tool to manage the translations. See http://translations.piwik.org Feel free to register and do changes there. All changes will be merged to git automatically from time to time.
Oops, sorry, I didn't find the information on http://piwik.org/get-involved/. As the changes are minors, would you rather do the changes yourself please :) ?
Sure, I've done that right now. But please consider registering there, nevertheless. Maybe you could help translating untranslated parts of Piwik.