message: Document place code type
diff: @@ -490,7 +490,7 @@ block content
  h3#Place-Lookup Place Lookup
  - p Lookup a place by code. Returns all available data if found. Returns 404 if place does not exist.
  + p Find a place by OSGB code (e.g. "osgb4000000074564391"). Returns all available data if found. Returns 404 if place does not exist.
  pre
  h4 https://api.postcodes.io/places/:code
  