apidoc: Fix @arg and @exception decorator data loss
apidoc: Fix @arg and @exception decorator data loss

The code was badly indented.

This actually lost some @arg parameter which ultimately created the
wrong links. In effect, before that fix, only one argument could ever be
passed along.

This also fixes the generation of possible exceptions raised by the api.
In a similar manner, only one exception would ever be listed before that
fix.

Closed T623
Related T622

SoftwareHeritage/swh-web-ui,SoftwareHeritage/swh-web-ui,SoftwareHeritage/swh-web-ui