Updated RPC API (markdown)

RPC-API.md

@@ -96,15 +96,23 @@ This is an example response to a `berlin` query param :
 curl --data-binary '{"jsonrpc": "2.0", "method": "get_element", "params": {"id": "node:12141608846"}, "id": 1}' https://api.btcmap.org/rpc
 ```
 
-### Example reponse
+### Example response
 
 _TODO_
 
 ## set_element_tag
 
-- token
-- name
-- value
+This sets tags on elements within BTC Map only - these are not tags directly on OSM elements.
+
+### Params
+
+`id` : OSM element in the form `element_type:id`. e.g. `node:12345` or `way:12345`.
+
+`name` : Tag name. Free text.
+
+`value` : Tag value. Free text.
+
+### Example request
 
 ```bash
 curl --data-binary '{"jsonrpc": "2.0", "method": "set_element_tag", "params": {"id": "node:12141608846", "name": "foo", "value": "bar"}, "id": 1}' https://api.btcmap.org/rpc