Code Inspection: Use preferred style for trailing comma when last element is not followed by a new line
This code inspection checks that trailing commas in single-line declarations with multiple items and similar constructs (object, array, and collection initializers, as well as enums and switch expressions) conform to your code style.
Depending on your preferences, it either detects redundant trailing commas or missing trailing commas.
The preferences are configured on the Alt+R, O), under Trailing comma.
page of ReSharper options( Last modified: 08 March 2021