Review the `field:coding_rate key:description` value

[mkinney]

From the Chinese translation:

"The field:coding_rate key:description has an example explaining the concept of denominator. However, in the original English text, it says ie for 4/8, the value is 8. 5/8 the value is 5, which is not correct. I believe the correct expression would be ie for 4/8, the value is 8. 4/5 the value is 5. Didn't touch the original text but the translation is corrected."