update tcp stream documentation

[chathaway-codes]

A small styling issue that seemed inconsistent here when compared to other places (such as https://doc.rust-lang.org/beta/std/net/struct.TcpListener.html).

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @Kimundi (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

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[rust-highfive]

The job x86_64-gnu-llvm-5.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

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[01:31:21] ...iiii...............................................
[01:31:21] failures:
[01:31:21] failures:
[01:31:21] 
[01:31:21] ---- net/tcp.rs - net::tcp::TcpStream (line 42) stdout ----
[01:31:21] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `std::ops::Try`)
[01:31:21]  --> net/tcp.rs:47:22
[01:31:21]   |
[01:31:21] 8 |     let mut stream = TcpStream::connect("127.0.0.1:34254")?;
[01:31:21]   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `()`
[01:31:21]   = help: the trait `std::ops::Try` is not implemented for `()`
[01:31:21]   = note: required by `std::ops::Try::from_error`
[01:31:21] 
[01:31:21] 
[01:31:21] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `std::ops::Try`)
[01:31:21]   --> net/tcp.rs:49:5
[01:31:21]    |
[01:31:21] 10 |     stream.write(&[1])?;
[01:31:21]    |     ^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `()`
[01:31:21]    = help: the trait `std::ops::Try` is not implemented for `()`
[01:31:21]    = note: required by `std::ops::Try::from_error`
[01:31:21] 
[01:31:21] 
[01:31:21] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `std::ops::Try`)
[01:31:21]   --> net/tcp.rs:50:5
[01:31:21]    |
[01:31:21] 11 |     stream.read(&mut [0; 128])?;
[01:31:21]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `()`
travis_time:end:1e2479b2:start=1539186485505106178,finish=1539191967116993912,duration=5481611887734

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:02323479

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[chathaway-codes]

My bad; didn't realize the code comments were being compiled for checking. I'll fix it and test locally then push a new commit

[TimNN]

Ping from triage @Kimundi / @rust-lang/docs: This PR requires your review.

[GuillaumeGomez]

Thanks!

@bors: r+ rollup

[bors]

📌 Commit 4530b8c has been approved by GuillaumeGomez

[kennytm]

@bors r-

Wrongly reappeared on bors queue