Add `Rasterband::set_statistics`

[netthier]

• [x] I agree to follow the project's code of conduct.
• [x] I added an entry to CHANGES.md if knowledge of this change could be valuable to users.

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This PR adds safe bindings for https://docs.rs/gdal-sys/latest/gdal_sys/fn.GDALSetRasterStatistics.html (https://gdal.org/api/gdalrasterband_cpp.html#_CPPv4N14GDALRasterBand13SetStatisticsEdddd). I also fixed up the docs for get_statistics where a backtick was missing.

[netthier]

It could maybe make sense to have the method take StatisticsAll instead.