Merge pull request webpack#7544 from Legends/CompatabilityPlugin

CompatabilityPlugin typings added

Author: sokra

lib/CompatibilityPlugin.js

@@ -8,7 +8,14 @@ const ConstDependency = require("./dependencies/ConstDependency");
 
 const NullFactory = require("./NullFactory");
 
+/** @typedef {import("./Compiler.js")} Compiler */
+
 class CompatibilityPlugin {
+	/**
+	 * Apply the plugin
+	 * @param {Compiler} compiler Webpack Compiler
+	 * @returns {void}
+	 */
 	apply(compiler) {
 		compiler.hooks.compilation.tap(
 			"CompatibilityPlugin",