Documented the block body for the GRIN wiki website

[marekyggdrasil]

human readable version for the review: https://github.com/marekyggdrasil/docs/blob/master/docs/wiki/blocks/block-body.md

[tromp]

See in-line comments.

[marekyggdrasil]

@tromp for your convenience during the review

NRD Kernels
https://github.com/marekyggdrasil/docs/blob/master/docs/wiki/transactions/transaction-body.md#nrd-no-recent-duplicate-kernels

Block body is transaction body
https://github.com/marekyggdrasil/docs/blob/master/docs/wiki/blocks/block-body.md

[tromp]

Thanks for addressing earlier comments.
I have a few more requests for changes. See in-line comments.

[marekyggdrasil]

I resolved your comments @tromp could you please take another look?

[tromp]

Looks fine.

[marekyggdrasil]

Thanks for the review @tromp .

[Anynomouss]

Is there a good reason why this has not been merged yet...?