Refactor to enumerate from "range and len" as pylint suggests

results in simpler and faster code, see
#56 (comment)

Author: generalmimon

kaitaistruct.py

@@ -397,8 +397,8 @@ def process_rotate_left(data, amount, group_size):
         anti_amount = -amount & mask
 
         r = bytearray(data)
-        for i in range(len(r)):  # pylint:disable=consider-using-enumerate
-            r[i] = (r[i] << amount) & 0xff | (r[i] >> anti_amount)
+        for i, byte in enumerate(r):
+            r[i] = (byte << amount) & 0xff | (byte >> anti_amount)
         return bytes(r)
 
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