sqlcommenter: put the comment at the beginning of the query

[jakub-mikians-airspace-intelligence]

Hi!

sqlcommenter appends the comment to the end of the query. I would propose prepending the comment at the beginning of the query instead.

The comment at the end is problematic when the query is really long, and the comment is truncated from database query logs. The very long queries are often produced by Django, and the query logs (e.g. top slow queries) have limited length in AWS RDS.

What do you think?