Change railway:turnout_side field from combo to radio

[FloEdelmann]

Description, Motivation & Context

Easier to see, and removes the need for querying taginfo statistics for this field.

Related issues

• Part of Decrease the number of dropdowns #2049

Links and data

Relevant OSM Wiki links:

• https://wiki.openstreetmap.org/wiki/Tag:railway%3Dswitch

Relevant tag usage stats:

• https://taginfo.openstreetmap.org/keys/railway%3Aturnout_side

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## Test-Documentation

### Preview links & Sidebar Screenshots

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### Wording

- [ ] American English
- [ ] `name`, `aliases` (if present) use Title Case
- [ ] `terms` (if present) use lower case, sorted A-Z
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[FloEdelmann]

Test-Documentation

Preview links & Sidebar Screenshots

railway=switch with railway:turnout_side=right: https://pr-2267--ideditor-presets-preview.netlify.app/id/dist/#locale=en&map=19.93/48.10963/11.73861&background=Bing&id=n1180641481

railway=switch without railway:turnout_side: https://pr-2267--ideditor-presets-preview.netlify.app/id/dist/#locale=en&map=19.93/48.11072/11.73371&background=Bing&id=n1180641606

[matkoniecz]

though it looks like taginfo was not queried already