quote operative in error messages

lib/voicemeeter/configs.rb

@@ -87,7 +87,7 @@ module Voicemeeter
       def initialize(kind)
         @kind = kind
         @configs = Hash.new do |hash, key|
-          raise Errors::VMError.new "unknown config #{key}. known configs: #{hash.keys}"
+          raise Errors::VMError.new "unknown config '#{key}'. known configs: #{hash.keys}"
         end
         @filereader = FileReader.new(kind)
       end

lib/voicemeeter/remote.rb

@@ -112,7 +112,7 @@ module Voicemeeter
       kind = Kinds.get(kind_id)
     rescue KeyError => e
       logger.error "#{e.class.name}: #{e.message}"
-      raise Errors::VMError.new "unknown Voicemeeter kind #{kind_id}"
+      raise Errors::VMError.new "unknown Voicemeeter kind '#{kind_id}'"
     else
       RequestRemote.for(kind, **)
     end