-t overshadowed by jekyll built-in -t

[courajs]

-t is already claimed by the --trace option. We should choose another short flag or remove it, since it doesn't work as documented.

[courajs]

I'm thinking -m --markup would be good. We could also use either -e or -x with --extension, or just drop -t and leave the --type long flag.

[parkr]

I like both! Extension is probably better.

[courajs]

Fixed in eca6e26