NS_ENUM and NS_OPTIONS formatting fixes

This pull request fixes a few issues in documenting enumerations. Some were introduced after the addition of slash prefixes and some were already there prior to that change. The changes are best described with examples:

#### NS_OPTIONS syntax

```objc
typedef NS_OPTIONS(NSUInteger, SampleEnum) {
    SampleValue1,
    SampleValue2
};
```

#### Before

```objc
/**
 * <#Description#>
 */
typedef NS_OPTIONS(NSUInteger, SampleEnum) {
    SampleValue1,
    SampleValue2
};
```

#### After

```objc
/**
 * <#Description#>
 */
typedef NS_OPTIONS(NSUInteger, SampleEnum) {
    /**
     * <#Description#>
     */
    SampleValue1,
    /**
     * <#Description#>
     */
    SampleValue2
};
```

### Opening brace on separate line

```objc
typedef NS_ENUM(NSUInteger, SampleEnum) 
{
    SampleValue1,
    SampleValue2
};
```

#### Before

```objc
/**
 * <#Description#>
 */
typedef NS_ENUM(NSUInteger, SampleEnum) 
{
    SampleValue1,
    SampleValue2
};
```

#### After

```objc
/**
 * <#Description#>
 */
typedef NS_ENUM(NSUInteger, SampleEnum) 
{
    /**
     * <#Description#>
     */
    SampleValue1,
    /**
     * <#Description#>
     */
    SampleValue2
};
```

### Excess newlines in enum

```objc
typedef NS_ENUM(NSUInteger, SampleEnum) {

    SampleValue1,

    SampleValue2

};
```

#### Before

```objc
/**
 * <#Description#>
 */
typedef NS_ENUM(NSUInteger, SampleEnum) {
    /**
     * <#Description#>
     */
    
    SampleValue1,
    /**
     * <#Description#>
     */
    
    SampleValue2
};
```

#### After

```objc
/**
 * <#Description#>
 */
typedef NS_ENUM(NSUInteger, SampleEnum) {
    /**
     * <#Description#>
     */
    SampleValue1,
    /**
     * <#Description#>
     */
    SampleValue2
};
```

### Slash Prefix

```objc
typedef NS_ENUM(NSUInteger, SampleEnum) {
    SampleValue1,
    SampleValue2
};
```

#### Before

```objc
/// <#Description#>

typedef NS_ENUM(NSUInteger, SampleEnum) {
    /// <#Description#>
    
    SampleValue1,
    /// <#Description#>
    
    SampleValue2
};
```

#### After

```objc
/// <#Description#>
typedef NS_ENUM(NSUInteger, SampleEnum) {
    /// <#Description#>
    SampleValue1,
    /// <#Description#>
    SampleValue2
};
```