Ported test suite: plugin-resolution (#42)

- We currently don't support loading plugins with implicit relative paths (missing starting dot)

Author: 43081j

test/__fixtures__/plugins/absolute-path/prettier.config.mjs

@@ -0,0 +1,7 @@
+import path from 'node:path'
+
+export default {
+  plugins: [
+    path.resolve('../../../../../config/prettier-plugins/prettier-plugin-uppercase-rocks/index.js')
+  ]
+}

test/__fixtures__/plugins/automatic/file.txt

@@ -0,0 +1 @@
+contents