container: hledger-flow: ethereum-based: support non-alpha chars (currency)

- Fixes broken import of any tx that contains non-alpha character(s) in
  its currency (digits, etc.)
  * Currencies may now contain any character(s) supported by hledger

container/src/hledger-flow/accounts/blockchain-explorers/ethereum-based/ethereum-based-shared.rules

@@ -22,7 +22,7 @@ date-format %Y-%m-%d %H:%M:%S
 description %date +0000
 
 account1 assets:%account_name:%subaccount_name:%blockchain:%symbol
-amount %amount_ %symbol
+amount %amount_ "%symbol"
 
 comment blockchain:%blockchain, type:%type, block:%block_number, blockid:%block_hash, index:%tx_index, method:%method_id, subaccount_address:%subaccount_address, from_address:%from_address, to_address:%to_address, txid:%tx_hash, direction:%direction
 
@@ -39,7 +39,7 @@ if %token_id [0-9]
 
 # Subtract when sending OUT
 if %direction ^OUT$
-  amount -%amount_ %symbol
+  amount -%amount_ "%symbol"
 
 # Default transfers as equity accounts
 if %direction ^IN$