Moves comments when reformatting data, only if necessary

[pbrisbin]

Given an ill-formed data declaration, Brittany will fix it, but messes up the comments in the process:

Before:

data Example
  = Example
  { example :: Int
  -- ^ Comment
  , example :: Int
  -- ^ Comment
  , example :: Int
  }

After:

data Example = Example
  { example :: Int
             -- ^ Comment
  , example :: Int
             -- ^ Comment
  , example :: Int
  }

However, if the declaration is already well-formed:

data Example = Example
  { example :: Int
  -- ^ Comment
  , example :: Int
  -- ^ Comment
  , example :: Int
  }

The comments don't move.

Our configuration

```yaml --- conf_debug: dconf_roundtrip_exactprint_only: false dconf_dump_bridoc_simpl_par: false dconf_dump_ast_unknown: false dconf_dump_bridoc_simpl_floating: false dconf_dump_config: false dconf_dump_bridoc_raw: false dconf_dump_bridoc_final: false dconf_dump_bridoc_simpl_alt: false dconf_dump_bridoc_simpl_indent: false dconf_dump_annotations: false dconf_dump_bridoc_simpl_columns: false dconf_dump_ast_full: false conf_forward: options_ghc: - -XBangPatterns - -XDataKinds - -XDeriveAnyClass - -XDeriveFoldable - -XDeriveFunctor - -XDeriveGeneric - -XDeriveLift - -XDeriveTraversable - -XDerivingStrategies - -XFlexibleContexts - -XFlexibleInstances - -XGADTs - -XGeneralizedNewtypeDeriving - -XLambdaCase - -XMultiParamTypeClasses - -XNoImplicitPrelude - -XNoMonomorphismRestriction - -XOverloadedStrings - -XRankNTypes - -XRecordWildCards - -XScopedTypeVariables - -XStandaloneDeriving - -XTypeApplications - -XTypeFamilies conf_errorHandling: econf_ExactPrintFallback: ExactPrintFallbackModeInline econf_Werror: false econf_omit_output_valid_check: false econf_produceOutputOnErrors: false conf_preprocessor: ppconf_CPPMode: CPPModeAbort ppconf_hackAroundIncludes: false conf_obfuscate: false conf_roundtrip_exactprint_only: false conf_version: 1 conf_layout: lconfig_reformatModulePreamble: true lconfig_altChooser: tag: AltChooserBoundedSearch contents: 3 lconfig_allowSingleLineExportList: false lconfig_importColumn: 60 lconfig_hangingTypeSignature: false lconfig_importAsColumn: 50 lconfig_alignmentLimit: 1 lconfig_indentListSpecial: true lconfig_indentAmount: 2 lconfig_alignmentBreakOnMultiline: true lconfig_cols: 80 lconfig_indentPolicy: IndentPolicyLeft lconfig_indentWhereSpecial: true lconfig_columnAlignMode: tag: ColumnAlignModeDisabled contents: 0.7 ```

% stack exec brittany -- --version
brittany version 0.13.1.0
Copyright (C) 2016-2019 Lennart Spitzner
Copyright (C) 2019 PRODA LTD
There is NO WARRANTY, to the extent permitted by law.