enhance oreKey: not only primitive but any struct can be used

[duongphuhiep]

• not only primitive but any struct can be used for Key, as long as the key type is comparable.
• no need test for nil key, because passing nil value as key won't compile.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[firasdarwish]

this solves a very annoying issue, thank you @duongphuhiep