correct example in EditEntity API module

'site' instead of 'language' and 'title' instead of 'value'
were used for a description

the glitch was introduced in Ice9e210139796956c5ad17e30b2345c179ce9a6c

first reported on Wikidata:
https://www.wikidata.org/wiki/?oldid=122735390#Error_in_documentation

Change-Id: Idd232762400843a6be5c1b456256bd004a9ba604
Merge "correct example in EditEntity API module"