Hello. I am not sure, but 'can be include directives' looks very strange to me: As for pg_hba.conf, the lines in this file can be include directives, following the same rules.
I suppose it should be 'can include directives' or similar.
Thanks.
Actually "include directive" here is a technical term and the entire phrase is indeed correctly spelled.
("Include directive" is a line directing the configuration file processor to read in the contents of the specified file as if it were literally included here.)