Reset the ERR counters when pressing the c key. This only makes the
current pw-top start counting from 0 again, it does not change anything
globally on the server. It's still usefull because you can use it to
let it count the number of new errors since the keypress.
Use (fixed-up) Doxygen manpage output for all program & module manpages.
This also allows formatting the manual pages properly in the HTML docs.
The Markdown pages work properly only with Doxygen >= 1.9.7, older
versions put them to wrong place in the HTML docs.
