Add crossing=informal as unsearchable preset for point and line geometries

[mikaeldui]

I'm currently adding a lot of informal paths, and just stumbled upon one that crosses a large road. I thought I'd add a crossing for the point but there was no preset for informal crossings. I almost made it an unmarked crossing but after browsing the wiki it seems informal crossing is correct. However, there's currently no preset for informal crossings which makes it hard to add, even harder as they shouldn't have the highway tag.

Informal crossings are well documented on the Wiki: https://wiki.openstreetmap.org/wiki/Tag:crossing%3Dinformal

[github-actions]

🍱 You can preview the tagging presets of this pull request here.

[tyrasd]

This would address / fix #1056

[tordans]

I ran into this again the other day and think we should merge this as an unsearchable preset for now.

Out in the wil:
Since SC uses the tag, there are crossings that just don't show up right ATM, eg (from GoMap):

I think we should support this since SC supports it.

However, it should be unsearchable IMO, because…

• the think the wiki page is quite bad for this tag https://wiki.openstreetmap.org/wiki/Tag:crossing%3Dinformal
• the reasoning why it is used is not easy to find, apparently somewhere in this forum thread at SC wants to create duplicate kerb tags streetcomplete/StreetComplete#4944
• I did not see any of those crossings in the wild which I would actually consider informal crossings. The wiki shows a good example, but the cases I saw in cities are all unmarked IMO.

I changes a few things in this PR:

1. I made the preset unsearchable
2. I added a corresponding line based preset to give users a way to use the same logic when mapping sidewalks as separate geometries. Those are only use 2k times for now, but keeping line and point data in sync is important IMO.
   In my example below the used did not add any sub tag "crossing type" at all, which is not better IMO https://www.openstreetmap.org/way/1079416103. Also, once we have Adopt Rapid's sidewalk and curb mapping improvements to iD iD#10757 in place point and line data should have a match.

   

One thing I did not add is a translated value for the crossing=* field which means this value still shows up as a raw value

Given the state of the tagging described above I think we should keep it this way. It would be very hard to find a 2-3 word name for those crossings that will be easy to understand for users. SC has more context that it can use to guide users and still there are miss matches. I fear that promoting the tag further is too early.

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Testing:

https://pr-1140--ideditor-presets-preview.netlify.app/id/dist/#locale=en&disable_features=boundaries&map=20.30/52.46062/13.53049&background=Bing&id=n9894826209

Data item looks good:

Icon looks good:
It uses the same as unmarked which is fitting.

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Closes #1056
Checks one box in #1410

[tordans]

@tyrasd I merged this now but you might want to double check this. My reasoning is in #1140 (comment)