Fix broken tests, add docs

Author: ntdb

docs/rules/newline-after-import.md

@@ -1,9 +1,11 @@
 # newline-after-import
 
-Enforces having an empty line after the last top-level import statement or require call.
+Enforces having one or more empty line after the last top-level import statement or require call.
 
 ## Rule Details
 
+This rule has one option, `newlines` which sets the number of newlines that are enforced after the last top-level import statement or require call. This option defaults to `1`.
+
 Valid:
 
 ```js
@@ -26,7 +28,7 @@ const BAR = require('./bar')
 const BAZ = 1
 ```
 
-...whereas here imports will be reported:
+Invalid:
 
 ```js
 import * as foo from 'foo'
@@ -46,6 +48,40 @@ const BAZ = 1
 const BAR = require('./bar')
 ```
 
+With `newlines` set to `2` this will be considered valid:
+
+```js
+import defaultExport from './foo'
+
+
+const FOO = 'BAR'
+```
+
+With `newlines` set to `2` these will be considered invalid:
+
+```js
+import defaultExport from './foo'
+const FOO = 'BAR'
+```
+
+```js
+import defaultExport from './foo'
+
+const FOO = 'BAR'
+```
+
+
+## Example options usage
+```
+{
+  ...
+  "rules": {
+    "import/newline-after-import": [{ "newlines": 2 }]
+  }
+}
+```
+
+
 ## When Not To Use It
 
 If you like to visually group module imports with its usage, you don't want to use this rule.

tests/src/rules/newline-after-import.js

@@ -83,7 +83,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     {
       code: `import foo from 'foo';\n\n\nvar foo = 'bar';`,
       parserOptions: { sourceType: 'module' },
-      options: { newlines: 2 },
+      options: [{ 'newlines': 2 }],
     },
     {
       code: `var foo = require('foo-module');\n\nvar foo = 'bar';`,
@@ -92,7 +92,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     {
       code: `var foo = require('foo-module');\n\n\nvar foo = 'bar';`,
       parserOptions: { sourceType: 'module' },
-      options: { newlines: 2 },
+      options: [{ 'newlines': 2 }],
     },
     {
       code: `require('foo-module');\n\nvar foo = 'bar';`,
@@ -165,7 +165,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `import foo from 'foo';\n\nexport default function() {};`,
-      options: { newlines: 2 },
+      options: [{ 'newlines': 2 }],
       errors: [ {
         line: 1,
         column: 1,