RFR: Added section on maintainer-pain [v5]

[Phil Race]

On Thu, 10 Dec 2020 23:04:15 GMT, Jesper Wilhelmsson <jwilhelm at openjdk.org> wrote:

>> Added section on maintainer-pain
>
> Jesper Wilhelmsson has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixed typo

Marked as reviewed by prr (no project role).

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

PR: https://git.openjdk.java.net/guide/pull/37