[ruby/resolv] Update resolv.rb - fix spelling

ruby/resolv@65ce7f214b

Author: jbampton

lib/resolv.rb

@@ -2601,7 +2601,7 @@ def initialize(flags, tag, value)
         end
 
         ##
-        # Flags for this proprty:
+        # Flags for this property:
         # - Bit 0 : 0 = not critical, 1 = critical
 
         attr_reader :flags