Tags with a dash inside doesn't work [b]-[/b] or [b]--[/b]

[robvdl]

This is a bit of a weird edge case, but after changing one of my sites to this library after the current one was no longer viable, I noticed that only a tag with a dash or multiple dashes inside won't get processed.

What works:

[b]a[/b]
[b]a-[/b]
[b]-a[/b]

What doesn't work:

[b]-[/b]
[b]--[/b]

It's a bit of an edge case though, not very common thing to do but a user did this :)