Thanks for the patch!
This does look like a documentation bug indeed.
I have a few comments:
1/ Remove this as
"(50% of the maximum, which is about 20GB),"
[1] tried to avoid explaining this level of detail, and I
agree with that.
2/ c/"about 10GB"/"10GB" the "about" does not seem necessary here.
[1] https://www.postgresql.org/message-id/flat/162395467510.686.11947486273299446208%40wrigleys.postgresql.org
Regards
Sami
Amazon Web Services (AWS)