Update postgresql.md

[rorpage]

Minor grammar and punctuation updates

Description:

Related issue (if applicable): Fixes #

Checklist (Required):

• The code change is tested and works locally.
• The code is compliant with Contributing guidelines

If pertinent:

• Script has validation check of the job.
• Created/Updated documentation at /docs

[homeassistant]

Hi @rorpage,

It seems you haven't yet signed a CLA. Please do so here.

Once you do that we will be able to review and accept this pull request.

Thanks!

[Landrash]

Looks good 👍