https://www.reuters.com/article/us-crypto-currency/musk-tweets-dogecoin-leaps-and-bitcoin-retreats-idUSKBN2CU2JC >LONDON/SINGAPORE (Reuters) -Bitcoin was heading on Friday for its worst week since February, while dogecoin leapt by a quarter, as the latest tweets on cryptocurrencies from Tesla boss Elon Musk sent the digital coins on a wild ride.