Simple edit, but makes welcome.html use proper HTML5 notation.
proper HTML5 DOCTYPE
added the correct DOCTYPE
updated with correct HTML5 notation
Thanks for the contribution. Eventually when this is translated it will probably be moved to the locale/ folder for each language and the lang attribute may need to change per language.
Actually, this page is probably being replaced in the next release by a new About page. I'll make sure it has the correct markup as seen in this fix.