Remove IO-related todo items

The open() sub has now been documented
The options to open() have now been documented.

Author: paultcochrane

lib/Language/io.pod

@@ -6,9 +6,7 @@
 
 =begin comment
 TODO: base on https://github.com/perl6/specs/blob/master/S32-setting-library/IO.pod?
-TODO: document http://doc.perl6.org/sub/open
 TODO: http://doc.perl6.org/type/IO::Handle has close but no open
-TODO: http://doc.perl6.org/routine/open does not describe any valid options
 =end comment
 
 =end pod