New UI option to configure problem severity for unused lambda parameters

[noopur2507]

See #1701 (comment).

Please note: eclipse-jdt/eclipse.jdt.core#3055 also introduces an API option to control whether unused lambda parameters should be complained against.

The option string is declared as:

public static final String OPTION_ReportUnusedLambdaParameter = "org.eclipse.jdt.core.compiler.problem.unusedLambdaParameter";

Note: This option has an effect only on JDK22 and upwards. For 21 and below, the compiler does not emit the unused lambda parameter warning - since these are not actionable.

[nlisker]

Lambdas are not the only places where unnamed patterns can occur: eclipse-jdt/eclipse.jdt.core#3054 (comment)
Are the other cases covered separately?

[noopur2507]

Opened eclipse-jdt/eclipse.jdt.core#3102 for the required API.

[noopur2507]

Lambdas are not the only places where unnamed patterns can occur: eclipse-jdt/eclipse.jdt.core#3054 (comment) Are the other cases covered separately?

This issue is only for the new UI option to configure the severity of compiler problem for unused lambda parameters i.e. under Preferences > Compiler > Errors/Warnings > Unnecessary code.

If other compiler problems need a UI option to configure the severity, please open separate issues for each.