RFR: Add material about updating the CSR when a backout occurs.

[Jesper Wilhelmsson]

On Wed, 9 Apr 2025 21:28:38 GMT, Stuart Marks <smarks at openjdk.org> wrote:

> Also, add a small fix to the Makefile.

Thank you for adding this! Looks good!

src/guide/testing-the-jdk.md line 339:

> 337: 
> 338: To backout a change with git, use `git revert`. This will apply (commit) the anti-delta of the change.
> 339: Then proceed as usual with creating a PR and getting it reviewed.

For consistency I'd prefer if this sentence was on the same line as the previous, since this is not a new paragraph. Not critical, but if you have the extra time :-)

-------------

Marked as reviewed by jwilhelm (Lead).

PR Review: https://git.openjdk.org/guide/pull/148#pullrequestreview-2754882687
PR Review Comment: https://git.openjdk.org/guide/pull/148#discussion_r2036187238