fix(docs): use require.resolve to ensure Yarn PnP compatibility

Use `require.resolve` both for:
 - webpack loader
 - finding path, previously it was built assuming that `node_modules` directory exists which is false in Plug'n'PLay mode

addons/docs/src/frameworks/common/preset.ts

@@ -66,7 +66,7 @@ export function webpack(webpackConfig: any = {}, options: any = {}) {
           include: new RegExp(`node_modules\\${path.sep}acorn-jsx`),
           use: [
             {
-              loader: 'babel-loader',
+              loader: require.resolve('babel-loader'),
               options: {
                 presets: [[require.resolve('@babel/preset-env'), { modules: 'commonjs' }]],
               },
@@ -77,11 +77,11 @@ export function webpack(webpackConfig: any = {}, options: any = {}) {
           test: /\.(stories|story).mdx$/,
           use: [
             {
-              loader: 'babel-loader',
+              loader: require.resolve('babel-loader'),
               options: createBabelOptions(babelOptions, configureJSX),
             },
             {
-              loader: '@mdx-js/loader',
+              loader: require.resolve('@mdx-js/loader'),
               options: {
                 compilers: [createCompiler(options)],
                 ...mdxLoaderOptions,
@@ -94,11 +94,11 @@ export function webpack(webpackConfig: any = {}, options: any = {}) {
           exclude: /\.(stories|story).mdx$/,
           use: [
             {
-              loader: 'babel-loader',
+              loader: require.resolve('babel-loader'),
               options: createBabelOptions(babelOptions, configureJSX),
             },
             {
-              loader: '@mdx-js/loader',
+              loader: require.resolve('@mdx-js/loader'),
               options: mdxLoaderOptions,
             },
           ],
@@ -112,7 +112,7 @@ export function webpack(webpackConfig: any = {}, options: any = {}) {
     result.plugins.push(
       new DllReferencePlugin({
         context,
-        manifest: path.join(coreDirName, 'dll', 'storybook_docs-manifest.json'),
+        manifest: require.resolve('@storybook/core/dll/storybook_docs-manifest.json'),
       })
     );
   }