Compressed style: Fix space removal after ancestor

    echo '.foo .bar{top:0}' | sassc/bin/sassc -t compressed

Before: `.foo.bar{top:0}`
After:  `.foo .bar{top:0}`

Fixes #2988

src/inspect.cpp

@@ -1054,14 +1054,21 @@ namespace Sass {
  }
  void Inspect::operator()(ComplexSelector* sel)
  {
- bool many = false;
  if (sel->hasPreLineFeed()) {
  append_optional_linefeed();
  }
+ const SelectorComponent* prev = nullptr;
  for (auto& item : sel->elements()) {
- if (many) append_optional_space();
+ if (prev != nullptr) {
+ if (typeid(*item) == typeid(SelectorCombinator) ||
+ typeid(*prev) == typeid(SelectorCombinator)) {
+ append_optional_space();
+ } else {
+ append_mandatory_space();
+ }
+ }
  item->perform(this);
- many = true;
+ prev = item.ptr();
  }
  }