[Po4a-devel]Spelling fixes in Sgml.pm

As I was reading Sgml.pm I found some spelling errors so I fixed them as I went. I know it's not as good as new functionality or bug fixes but at least that was an easy patch and it's one less thing for others to worry about :-) Changelog: * po4a/lib/Locale/Po4a/Sgml.pm Francois Gouget <fgouget(a)free.fr&gt; Assorted spelling fixes. -- Francois Gouget fgouget(a)free.fr http://fgouget.free.fr/ Linux, WinNT, MS-DOS - also known as the Good, the Bad and the Ugly.