doc: add the links to each method's document
doc: suppress the warning with YARD

[warn]: In file `lib/test/unit/notify.rb':38: Cannot resolve link to MAJOR from text:
[warn]: ...{MAJOR}...
[warn]: In file `lib/test/unit/notify.rb':38: Cannot resolve link to MINOR from text:
[warn]: ...{MINOR}...
[warn]: In file `lib/test/unit/notify.rb':38: Cannot resolve link to MICRO from text:
[warn]: ...{MICRO}...