tools/nxstyle: indent code against its enclosing brace, not modulo 4

A residue modulo four expresses neither the indentation unit nor the
alignment of case logic, and all of it was disabled from the first
switch to the end of the enclosing function.

Signed-off-by: raiden00pl <raiden00@railab.me>
Assisted-by: Claude Code

Author: raiden00pl