Implement operator<< for Suggestions

That way there’s no need to explicitely convert it to a string when
printing it

src/libutil/error.cc

@@ -285,7 +285,7 @@ std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool s
     auto suggestions = einfo.suggestions.trim();
     if (! suggestions.suggestions.empty()){
         oss << "Did you mean " <<
-            suggestions.trim().pretty_print() <<
+            suggestions.trim() <<
             "?" << std::endl;
     }
 

src/libutil/suggestions.cc

@@ -65,27 +65,27 @@ Suggestions Suggestions::trim(int limit, int maxDistance) const
     return Suggestions{res};
 }
 
-std::string Suggestion::pretty_print() const
+std::string Suggestion::to_string() const
 {
     return ANSI_WARNING + filterANSIEscapes(suggestion) + ANSI_NORMAL;
 }
 
-std::string Suggestions::pretty_print() const
+std::string Suggestions::to_string() const
 {
     switch (suggestions.size()) {
         case 0:
             return "";
         case 1:
-            return suggestions.begin()->pretty_print();
+            return suggestions.begin()->to_string();
         default: {
             std::string res = "one of ";
             auto iter = suggestions.begin();
-            res += iter->pretty_print(); // Iter can’t be end() because the container isn’t null
+            res += iter->to_string(); // Iter can’t be end() because the container isn’t null
             iter++;
             auto last = suggestions.end(); last--;
             for ( ; iter != suggestions.end() ; iter++) {
                 res += (iter == last) ? " or " : ", ";
-                res += iter->pretty_print();
+                res += iter->to_string();
             }
             return res;
         }
@@ -101,4 +101,14 @@ Suggestions & Suggestions::operator+=(const Suggestions & other)
     return *this;
 }
 
+std::ostream & operator<<(std::ostream & str, const Suggestion & suggestion)
+{
+    return str << suggestion.to_string();
+}
+
+std::ostream & operator<<(std::ostream & str, const Suggestions & suggestions)
+{
+    return str << suggestions.to_string();
+}
+
 }

src/libutil/suggestions.hh

@@ -16,7 +16,7 @@ public:
     int distance; // The smaller the better
     std::string suggestion;
 
-    std::string pretty_print() const;
+    std::string to_string() const;
 
     GENERATE_CMP(Suggestion, me->distance, me->suggestion)
 };
@@ -25,7 +25,7 @@ class Suggestions {
 public:
     std::set<Suggestion> suggestions;
 
-    std::string pretty_print() const;
+    std::string to_string() const;
 
     Suggestions trim(
         int limit = 5,
@@ -39,4 +39,7 @@ public:
 
     Suggestions& operator+=(const Suggestions & other);
 };
+
+std::ostream & operator<<(std::ostream & str, const Suggestion &);
+std::ostream & operator<<(std::ostream & str, const Suggestions &);
 }