Consistently declare JSpecify as a transitive compile-time dependency

[marcphilipp]

Overview

Prior to this commit this was only done in junit-platform-commons
which all other modules depend on. Therefore, JSpecify was already a
transitive compile-time dependency of all modules but their module
descriptors listed it as an non-transitive compile-time dependency.

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Definition of Done

• There are no TODOs left in the code
• Method preconditions are checked and documented in the method's Javadoc
• Coding conventions (e.g. for logging) have been followed
• Change is covered by automated tests including corner cases, errors, and exception handling
• Public API has Javadoc and @API annotations
• Change is documented in the User Guide and Release Notes