DOC: add doc on serverside

Please test examples.

src/caosdb/apiutils.py

@@ -637,6 +637,11 @@ def compare_entities(old_entity: Entity, new_entity: Entity):
                 newdiff["properties"][prop.name]["datatype"] = \
                     matching[0].datatype
 
+            if (prop.unit != matching[0].unit):
+                olddiff["properties"][prop.name]["unit"] = prop.unit
+                newdiff["properties"][prop.name]["unit"] = \
+                    matching[0].unit
+
             if (prop.value != matching[0].value):
                 olddiff["properties"][prop.name]["value"] = prop.value
                 newdiff["properties"][prop.name]["value"] = \