Add more hints to plugins validation requirements

[kabalin]

Following #326 it is now possible to enhance plugins validate tests with FileTokens::notFoundHint like used at https://github.com/moodlehq/moodle-plugin-ci/blob/main/src/PluginValidate/Requirements/FilterRequirements.php#L61 which will be added to output following the error:

X In filter.php, failed to find function call class_alias
X Hint: https://moodledev.io/docs/4.5/devupdate#filter-plugins

Adding those hints to other types of plugins validation requirements will improve developer experience (DevEx), making it easy to find relevant information to address the problem.