Ignore webserver for eslint (microsoft#166338)

Ignore webserver from eslint

Author: mjbvz

.eslintignore

@@ -15,6 +15,7 @@
 **/extensions/typescript-language-features/test-workspace/**
 **/extensions/typescript-language-features/extension.webpack.config.js
 **/extensions/typescript-language-features/extension-browser.webpack.config.js
+**/extensions/typescript-language-features/web/**
 **/extensions/vscode-api-tests/testWorkspace/**
 **/extensions/vscode-api-tests/testWorkspace2/**
 **/fixtures/**