Match HTML `p` tags in home page

The `prometheus.c` `home_page`  functuion outputs a set of information that have a structure like:

```
<h2>tite</h2>
bla bla
<p>
```

while it should be something like:

'''
<h2>title</h2>
<p>
bla bla
</p>
```

so that `p` tags are always matched. This does not cause at the moment any problem with browsers, but makes the HTML code cleaner and more correct.