chore: transition to shorter license headers (#6)

Transition from the GPL jumpscare to a more concise header:

	/*
     * Vencord, a Discord client mod
	 * Copyright (c) 2023 Vendicated and contributors
     *
	 * SPDX-License-Identifier: GPL-3.0
     */

Old files still keep the old headers, while eslint will now autofix the new header

Reviewed-on: https://codeberg.org/Ven/cord/pulls/6
Co-authored-by: Rini <rini@rinici.de>
Co-committed-by: Rini <rini@rinici.de>

patches/eslint-plugin-simple-header@1.0.1.patch

@@ -0,0 +1,13 @@
+diff --git a/src/index.js b/src/index.js
+index e8a8ee34fbafe310c75e752d59ba3a56109d67f1..6aecfe40f863823c8b115bca00537fcd78934137 100644
+--- a/src/index.js
++++ b/src/index.js
+@@ -95,7 +95,7 @@ function create(ctx) {
+         ?? [Array.isArray(options.text) ? options.text.join("\n") : options.text];
+ 
+     /** @type {string} */
+-    const src = ctx.sourceCode.getText();
++    const src = ctx.getSourceCode().getText();
+     const srcHeader = findHeader(src, syntax);
+     const headers = rawHeaders.map((raw) => makeComment(raw, syntax, decor));
+     const trailingLines = "\n".repeat(src.slice(srcHeader.length).trim() ? 1 + newlines : 1);