[1.21.4] Add support for double modifier keybinds

[ChampionAsh5357]

Closes #2012

Modifies the key lookup code to handle key mappings that use double modifiers (e.g. Ctrl + Shift). Most of the logic just goes towards allowing the key mappings to be pressed in any order while being removed properly from the associated map on release of either modifier.

[neoforged-pr-publishing]

• Publish PR to GitHub Packages

Last commit published: fdd898ae8edcd9a3fa01eb2bbd2d1b68dc8b3b22.

PR Publishing

The artifacts published by this PR:

• 📦 net.neoforged:neoforge:21.4.114-beta-pr-2014-fix-i2012
• 📦 net.neoforged:testframework:21.4.114-beta-pr-2014-fix-i2012

Repository Declaration

In order to use the artifacts published by the PR, add the following repository to your buildscript:

repositories {
    maven {
        name 'Maven for PR #2014' // https://github.com/neoforged/NeoForge/pull/2014
        url 'https://prmaven.neoforged.net/NeoForge/pr2014'
        content {
            includeModule('net.neoforged', 'neoforge')
            includeModule('net.neoforged', 'testframework')
        }
    }
}

MDK installation

In order to setup a MDK using the latest PR version, run the following commands in a terminal.
The script works on both *nix and Windows as long as you have the JDK bin folder on the path.
The script will clone the MDK in a folder named NeoForge-pr2014.
On Powershell you will need to remove the -L flag from the curl invocation.

mkdir NeoForge-pr2014
cd NeoForge-pr2014
curl -L https://prmaven.neoforged.net/NeoForge/pr2014/net/neoforged/neoforge/21.4.114-beta-pr-2014-fix-i2012/mdk-pr2014.zip -o mdk.zip
jar xf mdk.zip
rm mdk.zip || del mdk.zip

To test a production environment, you can download the installer from here.