[pavog]

A set of small, independent fixes for type and consistency issues in the analysis and detective classes.

Changes

• UnsupportedClassVersionProblem: Only add the UpdateJavaSolution if a Java version could be determined. Previously null could be passed to the solution's non-nullable constructor, resulting in a TypeError.
• MinecraftProblem: isEqual() now uses $insight instanceof static instead of comparing get_class() results. This matches how the subclasses that override isEqual() already check the type.
• Bukkit\PluginDependencyProblem: getDependencyPluginName() now returns string instead of ?string. The backing property is a non-nullable string, and this matches the Pocketmine counterpart.
• Detective: Use the correct class name casing WaterFallProxyLog::class, matching the class declaration and the import.

Behaviour notes

• MinecraftProblem::isEqual() is slightly broader than before
• Narrowing the return type of getDependencyPluginName() is compatible for callers, but a subclass overriding it with ?string would have to be adjusted.