Non-printing characters in some manpages

[JCGoran]

I've noticed that some manpages have non-printing characters in them; for instance, std::rand has this line (should be 0):

https://github.com/jeaye/stdman/blob/478d353c73bec79bbbad833a31c50eecd4578b46/man/std::rand.3#L9

According to grep, there's around 200 files that have the characters, which, comparing to the website versions, seem to almost always be characters in <span> tags, such as 0, a ;, a (, or whitespace, like the below:

1. whitespace (I think) https://github.com/jeaye/stdman/blob/478d353c73bec79bbbad833a31c50eecd4578b46/man/std::accumulate.3#L42

2. ; https://github.com/jeaye/stdman/blob/478d353c73bec79bbbad833a31c50eecd4578b46/man/std::condition_variable::wait_until.3#L66

3. ( https://github.com/jeaye/stdman/blob/478d353c73bec79bbbad833a31c50eecd4578b46/man/std::iterator_traits.3#L71

Some unicode characters also don't seem to be handled correctly:

https://github.com/jeaye/stdman/blob/478d353c73bec79bbbad833a31c50eecd4578b46/man/std::islower(std::locale).3#L43

It'd be nice if all of these could be parsed and rendered properly.