[tools] gtksourceview xpcc template highlighter: correct file extentions
[tools] gtksourceview xpcc template highlighter: correct file extentions

chrism333/xpcc,dergraaf/xpcc,dergraaf/xpcc,chrism333/xpcc,dergraaf/xpcc,chrism333/xpcc,dergraaf/xpcc,chrism333/xpcc