Function counter_id_to_symbol 

pub fn counter_id_to_symbol(counter_id: &str) -> String

Convert a counter_id back to a display symbol.

• ST/US/TSLA → TSLA.US
• ETF/US/SPY → SPY.US
• IX/US/.DJI → .DJI.US
• VA/HAS/BTCUSD → BTCUSD.HAS (crypto: PAIR.EXCHANGE)