Reduce whitespace in dbt_utils.star

[mjumbewu]

A call to {{ dbt_utils.star(this, relation_alias='x') }} previously would produce something like:

      

         x. 
  "column1"
 ,
        

         x. 
  "column2"
 ,
        

         x. 
  "column3"

Now produces:

x."column1",
x."column2",
x."column3"

The latter plays more nicely with the readability of the compiled sql. No leading or trailing whitespace, and just a newline between each column reference.

[clrcrl]

Thanks for this improvement!