Feature Request: document that the prepare-agent append configuration is true by default

Scenario

• JaCoCo version: 0.8.11.202310140853
• Operating system: MacOS (but most likely applies to any)
• Tool integration: Maven
• Description of your use case: maven with surefire plugin running unit tests

Current Behaviour

The prepare-agent documentation for the append configuration does not specify what the default value is.

It seems, based on my experimentation and reading the Jacoco source code, that the default value is true. This was unexpected to me because it means the build is less deterministic: multiple consecutive builds will accumulate coverage rather than each build starting from scratch. This can be confusing when removing test classes, because the coverage will not go down until a mvn clean is done.

I suppose it is too late to change the default to false (and you may have reasons for wanting it true, anyway). It seems like this could at least be documented, though.

Wanted Behaviour

Document that the default is true.

Start with the prepare-agent documentation's append configuration section and compare it with the default described in org.jacoco.core/src/org/jacoco/core/runtime/AgentOptions.java around line 287. Document that append defaults to true, then verify the generated documentation clearly shows the default value.