Add clarifying comment to cryptpacket_received function.

[hqwrong]

see #851

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This change is 

[sudden6]

Can you limit the line length to the same with as the rest of the code uses?

[hqwrong]

@sudden6 done

[sudden6]

Review status: 0 of 1 files reviewed at latest revision, all discussions resolved, some commit checks failed.

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toxcore/net_crypto.c, line 2759 at r1 (raw file):

 * return 0 on success.
 *
 * Note: The condition `buffer_end - buffer_start < pakcet_number - buffer_start` is

typo packet_number

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toxcore/net_crypto.c, line 2765 at r1 (raw file):

 * It CANNOT be simplified to `packet_number < buffer_start`, as it will fail
 * when `buffer_end < buffer_start`.
 *

please remove empty lines

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Comments from Reviewable

[sudden6]

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Review status: 0 of 1 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable