Better colors for compiler error mesasges (on white background you couldn't read them)

src/compiler/crystal/compiler.cr

@@ -76,7 +76,7 @@ module Crystal
         options_parser, inline_exp, filenames, arguments = process_options_internal(options)
       rescue ex : OptionParser::Exception
         print "Error: ".colorize.red.bold
-        puts ex.message.colorize.white.bold
+        puts ex.message.colorize.bold
         exit 1
       end
 
@@ -341,7 +341,7 @@ module Crystal
         end
         puts
         print "Error: ".colorize.red.bold
-        puts "you've found a bug in the Crystal compiler. Please open an issue: https://github.com/manastech/crystal/issues".colorize.white.bright
+        puts "you've found a bug in the Crystal compiler. Please open an issue: https://github.com/manastech/crystal/issues".colorize.bright
         exit 2
       end
     end

src/compiler/crystal/exception.cr

@@ -30,9 +30,9 @@ module Crystal
 
     def append_to_s(source, io)
       if @filename
-        io << "Syntax error in #{@filename}:#{@line_number}: #{@message.colorize.white.bold}"
+        io << "Syntax error in #{@filename}:#{@line_number}: #{@message.colorize.bold}"
       else
-        io << "Syntax error in line #{@line_number}: #{@message.colorize.white.bold}"
+        io << "Syntax error in line #{@line_number}: #{@message.colorize.bold}"
       end
 
       source = fetch_source(source)
@@ -166,7 +166,7 @@ module Crystal
       if @inner
         io << msg
       else
-        io << msg.colorize.white.bold
+        io << msg.colorize.bold
       end
     end