[doc] Fix multi-threading example in dining-philosophers

[rwz]

The current example does not illustrate threaded behavior imo.

[rust-highfive]

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[rwz]

Oh man, I didn't notice the philosophers names are different.

[alexcrichton]

The current example does actually show off multithreading, it's just not as interleaved as one might expect because you have to lock your fork on the table and if you can't you haven't started eating. The actual scenario where everyone starts eating all at once before anyone has finished is impossible because there aren't enough forks to go around.

Thanks for the PR though!

[rwz]

At the point that I've edited we still don't have any locks/forks. This is the example where everyone start at the same time, wait 1 second and then finish, roughly at the same time again. Mutexes (forks) are added in the next step. The output I've fixed reflects what I was actually getting implementing the example.

[alexcrichton]

Oh oops sorry, missed that part!

[alexcrichton]

@bors: r+ 49e4583 rollup

[bors]

⌛ Testing commit 49e4583 with merge a16a417...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt