Always output Sass values in error messages in expanded style

[nex3]

From sass/sass#1916:

Related to sass/sass-spec#627

I would like to requested that Sass values in error messages to always be output in the expanded style, or alternatively as authored. This is not the case currently.

foo {
  bar: (rgba(16,16,16,0.5) + #AAA);
}

Error: Alpha channels must be equal: rgba(16,16,16,0.5) + #AAA // compressed
Error: Alpha channels must be equal: rgba(16, 16, 16, 0.5) + #AAA // all other

[nex3]

I'm closing this issue as "on ice" because Ruby Sass is deprecated and no additional features are planned for it.