[RFC] notes.<REF>.rewriteMode configuration option

Hi all,

The project I work on currently heavily uses git. We would like to add some tools based around detecting how branches change over time for code review, so that users can compare commits as they change. We'd like to do this via adding metadata in git notes, so that we can detect when commits are ammended or squashed. While digging around in the `git notes` help, I noticed there is support for `notes.<ref>.mergeStrategy` but not `notes.<ref>.rewriteMode` configuration options. I was wondering if you would be interested in a patch that adds support for a `notes.<ref>.rewriteMode` configuration option that would take precedence for doing note rewrites for the given ref (like how `notes.<ref>.mergeStrategy` takes precedence for merges).

Regards, Barret Rennie