WAL Configuration Grammar Fix

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/11/wal-configuration.html
Description:

On the WAL Configuration page -
https://www.postgresql.org/docs/current/wal-configuration.html
It reads: "On Linux and POSIX platforms checkpoint_flush_after allows to
force the OS that pages written by the checkpoint should be flushed to disk
after a configurable number of bytes."

I believe a "you" is missing. I also suggest a more clear sentence
construction might be:
"On Linux and POSIX platforms you can use checkpoint_flush_after to set a
configurable number of bytes after which the OS will be forced to flush to
disk the pages written by the checkpoint."

Respectfully submitted.
Evan Macbeth