Whitespace cleanup: concat/current_timestamp/date_trunc/surrogate_key

[Limess]

Minor change to remove extraneous whitespace from concat/current_timestamp/date_trunc/surrogate_key macros.

Mainly actioned to reduce the vertical space taken up by surrogate_key, which we use almost everywhere, in the DBT compiled docs view.

Surrogate key test before:

select
    

    
        
    

    
        
    

    md5(cast(
  concat(coalesce(cast(field_1 as 
    varchar
), ''), '-', coalesce(cast(field_2 as 
    varchar
), ''), '-', coalesce(cast(field_3 as 
    varchar
), ''))
 as 
    varchar
)) as actual,
    expected

Surrogate key test after:

select
    md5(cast(concat(coalesce(cast(field_1 as 
    varchar
), ''), '-', coalesce(cast(field_2 as 
    varchar
), ''), '-', coalesce(cast(field_3 as 
    varchar
), '')) as 
    varchar
)) as actual,
    expected

This could still be much improved (not newlining types) but I'm unsure if that would break some scenarios in any SQL dialect supported by this package.

[clrcrl]

Closing in favor of #199 due to merge conflict