reflow of doc string

src/tools/flow_control.py

@@ -38,19 +38,21 @@ def crc(message):
     after all the characters of the message have been applied, is the CRC value.
     A procedure for generating a CRC is:
     
-     1. Load a 16–bit register with FFFF hex (all 1’s). Call this the CRC register. 
+    1. Load a 16–bit register with FFFF hex (all 1’s). Call this the CRC register.
-     2. Exclusive OR the first 8–bit byte of the message with the low–order byte of the 16–bit CRC register, putting the result in the 
+    2. Exclusive OR the first 8–bit byte of the message with the low–order byte of the 16–bit CRC register, putting the result in the
-        CRC register. 
+       CRC register.
-     3. Shift the CRC register one bit to the right (toward the LSB), zero–filling the MSB. Extract and examine the LSB. 
+    3. Shift the CRC register one bit to the right (toward the LSB), zero–filling the MSB. Extract and examine the LSB.
-     4. (If the LSB was 0): Repeat Step 3 (another shift). 
+    4. (If the LSB was 0): Repeat Step 3 (another shift).
-        (If the LSB was 1): Exclusive OR the CRC register with the polynomial value 0xA001 (1010 0000 0000 0001). 
+       (If the LSB was 1): Exclusive OR the CRC register with the polynomial value 0xA001 (1010 0000 0000 0001).
-     5. Repeat Steps 3 and 4 until 8 shifts have been performed. When this is done, a complete 8–bit byte will have been 
+    5. Repeat Steps 3 and 4 until 8 shifts have been performed. When this is done, a complete 8–bit byte will have been
-        processed. 
+       processed.
-     6. Repeat Steps 2 through 5 for the next 8–bit byte of the message. Continue doing this until all bytes have been processed. 
+    6. Repeat Steps 2 through 5 for the next 8–bit byte of the message. Continue doing this until all bytes have been processed.
-     7. The final content of the CRC register is the CRC value. 
+    7. The final content of the CRC register is the CRC value.
-     8. When the CRC is placed into the message, its upper and lower bytes must be swapped as described below. 
+    8. When the CRC is placed into the message, its upper and lower bytes must
+       be swapped as described below.
     
-    Placing the CRC into the Message 
+    Placing the CRC into the Message:
+    =================================
     When the 16–bit CRC (two 8–bit bytes) is transmitted in the message, the low-order byte will be transmitted first, followed by the high-
     order byte.
     """