Without this line, attempting to copy and paste non-ASCII characters
will result in error messages like the following (and pasting from the
server to the client will not work):
```
CLIPBOARD clipboard_send_data_response_for_text: 823 : ERROR: clipboard_send_data_response_for_text: bad string
```
Several service definitions used `mkEnableOption` with text starting
with "Whether to", which produced funny option descriptions like
"Whether to enable Whether to run the rspamd daemon..".
This commit corrects this, and adds short descriptions of services
to affected service definitions.