Change librustdoc write!(.. \n) to writeln!(..); fix comment grammar

[mautamu]

Howdy,

This PR does the following:

1. Updates the grammar of a comment in librustdoc.
2. Replaces a few write!(..\n) macros with writeln!(..\n) for clarity. (Please let me know if there is a reason why this might be wrong!)

Best,
Mautamu

[rust-highfive]

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[GuillaumeGomez]

Isn't writeln! using "\r\n" on windows? If so, it'd be very problematic.

[mautamu]

Isn't writeln! using "\r\n" on windows? If so, it'd be very problematic.

https://doc.rust-lang.org/std/macro.writeln.html
"On all platforms, the newline is the LINE FEED character (\n/U+000A) alone (no additional CARRIAGE RETURN (\r/U+000D)."

#[macro_export]
#[stable(feature = "rust1", since = "1.0.0")]
#[allow_internal_unstable(format_args_nl)]
macro_rules! writeln {
    ($dst:expr $(,)?) => (
        $crate::write!($dst, "\n")
    );
    ($dst:expr, $($arg:tt)*) => (
        $dst.write_fmt($crate::format_args_nl!($($arg)*))
    );
}

I think it's just calling \n? (I apologize if I'm referring to the wrong macro or missing something, not particularly familiar with macros).

[GuillaumeGomez]

No that seems correct, thanks for the confirmation! (I was only reading the source code and not the docs... Well, now I know sometimes reading docs is better haha).

[GuillaumeGomez]

r=me once CI pass

[mautamu]

Ah, thanks for double checking; I hadn't thought to look there! : )

[GuillaumeGomez]

@bors: r+ rollup

[bors]

📌 Commit 8db7973 has been approved by GuillaumeGomez