refactor(fmt): remove dead CallStack precall state

[phrwlk]

CallStack::precall_size was written in a few places but never read anywhere in the formatter. This effectively made it dead state and caused unnecessary writes on every formatted assignment or multi-var initialization. The field and its helper methods have been removed together with the corresponding calls in sol.rs.

The change keeps the existing formatting behavior intact by preserving the neverbreak logic and all indentation decisions. Only the unused tracking state was dropped to simplify the code and avoid future confusion when maintaining the call stack logic.