In nm-settings-nmcli, many properties are not well documented regarding the value's format and the accepted values.

• The format is many times inaccurate (i.e. uint32 instead of an enum)
• The accepted values are only documented in a manual way in some properties but not in others
• The same for special and/or aliased values (i.e. uint properties that accept "unknown" or "-1" as special value)

Properly document all this information for all the properties in nm-setting-nmcli.

Also, in the description texts, many times there appear references to C enum's value names, like `NM_IP_TUNNEL_MODE_IPIP (1)`. Those names are no meaningful for a nmcli user, so the values accepted by nmcli should appear instead, like `ipip (1)`.

Acceptance criteria:

Given The nm-settings-nmcli man page

When: there is a property of any type
Then: the “Format” field must show `bool / ternary / (u)int32/64 / string / EnumName (int32)` or other concise but descriptive text

When: there is a property that accept a list of elements of any type
Then: the “Format” field must show `list of` followed by the same format text than the type of the element’s type

When: there is a property that accepts any value of its type
Then: the field “Valid values” must not appear

When: there is a property without special/aliased values
Then: the field “Special values” must not appear

When: there is a property of type integer with a range of valid values
Then: the “Valid values” field must show `MIN - MAX`

When: there is a property of type integer or enum with a limited set of valid values
Then: the “Valid values” field must show `val_nick1 (NUM1), val_nick2 (NUM2) …`

When: there is a property of type flags
Then: the “Valid values” field must show `0x1 (flag_name1), 0x2 (flag_name2) …`

When: there is a property of type string with a limited set of valid values
Then: the “Valid values” field must show `val1, val2, val3, …`

When: there is a property of type integer or enum with special/aliased values:
Then: the “Special values” field must show `val_nick1 (NUM1), val_nick2 (NUM2) …`{}

When: there is a value of the enum marked as “internal”
Then: the value is not shown in the autogenerated documentation

When: a constant value is referenced in the sources' documentation comments
Then: it should appear in the man page with the format `value_nick (num)`

Definition of done:

• The nm-settings-nmcli man page contains the information described in the acceptance criteria for every property