Cleanup of the file

Consisting of three items:
 - Eliminate uses of is_subtype/2 in specs
 - Change module-local void functions to return 'ok' instead of []
 - Make sure there are no dialyzer warnings with --Wunmatched_returns
Change encoding of troublesome notes.xml files to utf-8

Most notes.xml files will be updated in every release and cause
the kind of the problems described in the previous commit.
Merge branch 'ks/hipe_unified_loader-cleanup/OTP-11301' into maint

* ks/hipe_unified_loader-cleanup/OTP-11301:
  Updated primary bootstrap
  Cleanup of the file
Merge branch 'bjorn/xml-encoding-fix/OTP-11310' into maint

* bjorn/xml-encoding-fix/OTP-11310:
  Change encoding of troublesome notes.xml files to utf-8
  Convert some notes.xml files from latin-1 to utf-8