Adds leaderboard support to PlaceholderAPI

[hudsonandres]

• Adds placeholders to display mcMMO leaderboard information through PlaceholderAPI.

• %mcmmo_mctop_<skill>:<position>%

• %mcmmo_mctop_overall:<position>%

• %mcmmo_mctop_name_<skill>:<position>%

• %mcmmo_mctop_name_overall:<position>%

• %mcmmo_checklevel_<skill>:<level>%

• Added a new explanatory file PLACEHOLDERS.md detailing all the placeholders that can be used.

[nossr50]

Looks like some stuff was included by accident that should be removed.

[Copilot]

Pull request overview

This PR adds leaderboard support to PlaceholderAPI, enabling server administrators to display mcMMO ranking information through placeholders in menus, scoreboards, and other UI elements.

• Implements five new placeholder types for leaderboard queries and level checks
• Adds comprehensive documentation file PLACEHOLDERS.md with usage examples
• Updates visibility of init() method from protected to private

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 13 comments.

Show a summary per file

File	Description
src/main/java/com/gmail/nossr50/placeholders/PapiExpansion.java	Adds getLeaderboard() helper method, registers new placeholder types, and changes init() visibility to private
src/main/java/com/gmail/nossr50/placeholders/OverallRankPlaceholder.java	New placeholder for displaying player's overall power level rank
src/main/java/com/gmail/nossr50/placeholders/McTopPositionPlaceholder.java	New placeholder for retrieving player name or level at specific leaderboard positions
src/main/java/com/gmail/nossr50/placeholders/CheckLevelPlaceholder.java	New placeholder for checking if player meets minimum skill level requirements
src/main/java/com/gmail/nossr50/listeners/BlockListener.java	Unrelated change: Modifies Fortune enchantment handling for block drops - should be in separate PR
PLACEHOLDERS.md	New documentation file detailing all available placeholders with examples and usage patterns

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[nossr50]

• Unit tests would probably be a good idea, you can mock up the responses from the DatabaseManager(s) and just validate the business logic here

[nossr50]

Just an update, been a bit busy irl this time of year, will be reviewing again soon, but this is likely to come in after the spears update.

[Chew]

By the way, I think the PLACEHOLDERS.md file might be better on the wiki repo here: https://github.com/mcMMO-Dev/mcmmo-wiki-repo/blob/master/placeholders.md. Excellent work on it!

[SrBedrock]

Why is a colon (:) used to separate the position instead of an underscore (_), which is the commonly adopted standard for placeholders in general?

[hudsonandres]

Why is a colon (:) used to separate the position instead of an underscore (_), which is the commonly adopted standard for placeholders in general?

I only kept the position structure from the original standard. PapiExpansion has a line for that: int dataPosition = params.indexOf(":");, however, it can be changed to underscore without any problem; a few adjustments are all that's needed to make it work.

[nossr50]

@hudsonandres if you add sufficient unit tests (preferably in Junit 5) I'd probably feel comfortable merging this, otherwise it's probably going to need to go into a dev branch when I find time to add them myself and then merge it into master later on, which would definitely slow down how quickly this feature would become available to others. Regarding the unit tests, feel free to mock up the responses and behavior from the DB classes as needed.