Add documentation for ecmaFeatures.globalReturn

Author: Kai Cataldo

README.md

@@ -81,15 +81,19 @@ Check out the [ESLint docs](http://eslint.org/docs/rules/) for all possible rule
 
 - `sourceType` can be set to `'module'`(default) or `'script'` if your code isn't using ECMAScript modules.
 - `allowImportExportEverywhere` (default `false`) can be set to `true` to allow import and export declarations to appear anywhere a statement is allowed if your build environment supports that. Otherwise import and export declarations can only appear at a program's top level.
+- `ecmaFeatures.globalReturn` (default `false`) allow return statements in the global scope when used with `sourceType: "script"`.
 
-**.eslintrc**
+**.eslintrc.json**
 
 ```json
 {
   "parser": "babel-eslint",
   "parserOptions": {
     "sourceType": "module",
     "allowImportExportEverywhere": false,
+    "ecmaFeatures": {
+      "globalReturn": false 
+    }
   }
 }
 ```

test/specs/non-regression.js

@@ -21,8 +21,6 @@ function verifyAndAssertMessagesWithSpecificESLint(
     parserOptions: {
       ecmaVersion: 2018,
       ecmaFeatures: {
-        jsx: true,
-        experimentalObjectRestSpread: true,
         globalReturn: true,
       },
       sourceType,
@@ -1155,9 +1153,6 @@ describe("verify", () => {
     ) {
       const overrideConfig = {
         parserOptions: {
-          ecmaFeatures: {
-            legacyDecorators: true,
-          },
           sourceType,
         },
       };