docs: Things that need manual fixing in Changelog/Migration guide

[gkalpak]

A list of things that might need manual fixing in the 1.6.0-rc.0 changelog and the related migraton guide section:

• 04cad41: It says BREAKING CHANGE (without trailing :). It will not be detected as a BC.
• e8c2e11: It says POSSIBLE BREAKING CHANGE. Make sure it is detected as a BC.
• 2456ab6: Forgot to add a BC notice (see refactor(ngResource): Use core encode methods in ngResource #14309 (comment)).
• 1547c75#commitcomment-19034659: Is a BC, but as refactor won't show up.
• input[range]: Add BC notice?
• fc0c11d: Last line of examples is wrong. It should be elem.data('foo-bar').
• d882fde: Raw HTML (must be wrapped in ...).

[petebacondarwin]

See #15311