Chore: Eslint include file fix

- https://typescript-eslint.io/linting/troubleshooting/#i-get-errors-telling-me-eslint-was-configured-to-run--however-that-tsconfig-does-not--none-of-those-tsconfigs-include-this-file

Parsing error: ESLint was configured to run on `src/transform-values/simply-important.ts` using `parserOptions.project`:
- <tsconfigRootDir>/tsconfig.json
- <tsconfigRootDir>/tsconfig.node.json
However, none of those TSConfigs include this file. Either:
- Change ESLint's list of included files to not include this file
- Change one of those TSConfigs to include this file
- Create a new TSConfig that includes this file and include it

configs/eslint-config-custom/index.js

@@ -3,7 +3,11 @@ const { defineConfig } = require('eslint-define-config');
 module.exports = defineConfig({
   $schema: "https://json.schemastore.org/eslintrc.json",
   parser: "@typescript-eslint/parser",
-  parserOptions: { ecmaVersion: 'latest', sourceType: 'module' },
+  parserOptions: {
+    ecmaVersion: "latest",
+    sourceType: "module",
+    EXPERIMENTAL_useProjectService: true
+  },
   plugins: [
     "@typescript-eslint",
     "prettier"

packages/css/tsconfig.json

@@ -1,6 +1,6 @@
 {
   "extends": "tsconfig-custom/tsconfig.json",
-  "include": ["./src/**/*.ts",  "__tests__/**.ts"],
+  "include": ["src/**/*.ts",  "__tests__/**/*.ts"],
   "exclude": ["dist"],
   "references": [{ "path": "tsconfig.node.json" }]
 }

packages/transform-to-vanilla/tsconfig.json

@@ -1,6 +1,6 @@
 {
   "extends": "tsconfig-custom/tsconfig.json",
-  "include": ["./src/**/*.ts",  "__tests__/**.ts"],
+  "include": ["src/**/*.ts",  "__tests__/**/*.ts"],
   "exclude": ["dist"],
   "references": [{ "path": "tsconfig.node.json" }]
 }