Extended "type" spec to allow for functions

Just dropping the word about a recent pull request I’ve done in github, related to markdown parsing.

Marijn, I wasn’t sure you would get a warning about it, but I know you read the forums. I did search for “pull request” in this forum before I did so, so if this was inappropriate you may want to create a topic with some guidelines for doing such pull requests (e.g. how long I should’ve waited before writing here, and so on).

Take care and thanks for all the work.