Comment in first line of definition (after equal sign)

## Problem

This is similar (and probably related) to #474, only with `=` instead of `do`:

Input haskell
```
val =
  -- comment
  some code
```

Expected output haskell (identical to input)
```haskell
val =
  -- comment
  some code
```

Actual output haskell
```haskell
val
  -- comment
 = some code
```
