Suspected typo in the ChainSync specification

[nfrisby]

This commit 0fc21ba introduced the following statement.

Additional remarks Note that by sending MsgFindIntersect, the server will not modify its read-pointer.

An engineer at Tweag (@Gipphe) mentioned that line to me just today, and I don't understand what's it's supposed to convey.

1. The mini protocol server doesn't send MsgFindIntersect, it only receives it.

2. Maybe it's a typo and should instead read like this?

Additional remarks Note that by sending MsgIntersectNotFound, the server will not modify its read-pointer.

[coot]

You're right @nfrisby. This was supposed to fix issue #3443.