[dev] [st] Bold Text should be bright?

Im not sure if this is right, but most Terminals seem to make bold text
also bright. Some programs, like htop for example, rely on this. As far
as i remember, the first 8 colors should be mapped to the second 8
colors for bold text.

Here is a patch that does this. With it applied, man pages and htop
looks the same in st as in rxvt.

greetings
stefan mark