[Formatter] Line Breaks for Nested Subgroup Blocks

[xterao]

Describe the bug
In SQL statements where subgroups are nested, line breaks are not inserted between consecutive ( characters if no spaces are present.

To Reproduce

WITH tables AS (( SELECT top -- No line breaks
             , no_pre_as AS AS_NAME
             , pre_as
             , clm3
~~~

Expected behavior
This update fixes the issue by modifying the PreProcessor to explicitly add a line break after each (, ensuring proper formatting of nested subgroups.