Support more keywords (Postgres)

[bernardoamorim7]

Is your feature request related to a problem? Please describe.

I have a difficult time using the extension with Postgres because some keywords aren't highlighted as they should, and it's especially difficult reading procedures sometimes because of that.

Describe the solution you'd like

Add more keywords to the regexp that looks for keywords in language/sql.tmLanguage.json

The keywords I have right now are:
elsif|raise|notice|exception|warning|conflict|do|nothing|default|varying|add|column|tablespace|temporary|for|each|index|trigger|rename

Adding this to the end of the regexp fixes the issue for my use case.

Describe alternatives you've considered

I have no other alternative as of right now, perhaps there's a better option I can't think of?