Add additional condition for announcements

[Robbendebiene]

Currently we are not asking announcements for platforms that do not have a train=yes tag like: https://www.openstreetmap.org/way/220720360 We do this, because we do not want to ask this question for tram platforms. If this tag is missing tram platforms are indistinguishable from train platforms because the railway tag doesn't differentiate between them.
So asking this question simply if railway=platform is set would show this question for a lot of tram stops like: https://www.openstreetmap.org/way/217791160

As a compromise we could only ask this question for railway=platform if it is mapped as an area, because it is more likely to be a platform for trains then.

[wielandb]

Would we still need this precaution if #187 would be merged?
Maybe this PR could then be changed to explicitly only ask the announcement question if train=yes is set.

[Robbendebiene]

@wielandb Yes we will probably close this PR in favour of a new PR that addresses this. There are multiple conditions that could be improved based on #182