man: improve documentation of deprecated properties
The documentation of property deprecation was not great in nm-settings-nmcli(5).
This aims to improve that, essentially changing:
number
Legacy setting that used to help establishing PPP data sessions for GSM-based modems. Deprecated: 1
Into
number
Legacy setting that used to help establishing PPP data sessions for GSM-based modems.
This property is deprecated since version 1.16. User-provided values for this setting are no longer used.