Please add an icon to recreation_ground

[BertMule]

I have modelled quite a lo of recreation_ground. They have a clear function, and fortunately also a distinct colour.

But it would make them better recognisable if they also had an icon.

[imagico]

It is doubtful that a symbol can be developed that meaningfully represents what landuse=recreation_ground is practically used for. For a previous discussion of the semantic problems of the tag see #4572.