[fix] #101 fix sphinx warning on docstring

/home/vit/Documents/dev/python/duniter-python-api/duniterpy/documents/transaction.py:docstring of duniterpy.documents.transaction.Transaction.compact:6: WARNING: Block quote ends without a blank line; unexpected unindent.

duniterpy/documents/transaction.py

@@ -847,14 +847,14 @@ Currency: {1}
 
         :return:
 
-        "TX:VERSION:NB_ISSUERS:NB_INPUTS:NB_UNLOCKS:NB_OUTPUTS:HAS_COMMENT:LOCKTIME
+        TX:VERSION:NB_ISSUERS:NB_INPUTS:NB_UNLOCKS:NB_OUTPUTS:HAS_COMMENT:LOCKTIME
         PUBLIC_KEY:INDEX
         ...
         INDEX:SOURCE:FINGERPRINT:AMOUNT
         ...
         PUBLIC_KEY:AMOUNT
         ...
-COMMENT"
+        COMMENT
 """
         doc = "TX:{0}:{1}:{2}:{3}:{4}:{5}:{6}\n".format(
             self.version,