doc/book/getting-started.md: Spelling correction and revised wording.

[justsostephen]

The word 'Internet' was spelt with both an uppercase and a lowercase 'I'. The correct spelling seems to be a matter of some debate these days, however the first occurrence in the file has an uppercase 'I', so I've changed the second occurrence to suit for consistency.

Under the section titled 'Converting to Cargo', there's mention of creating a new executable. This, however, is not part of the process described. I've revised the wording to reflect as much.

Small changes, but I hope they are of benefit! :-)

r? @steveklabnik

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @steveklabnik (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 Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed.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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[GuillaumeGomez]

Thanks for your work! Please squash your commits.

[steveklabnik]

In this case, I think it's okay to leave them unsquashed: they are two logical changes, even though they are both small.

Thanks so much!

@bors: r+ rollup

[bors]

📌 Commit 018c595 has been approved by steveklabnik

[justsostephen]

You're most welcome!

I came across the rewrite of "The Book" (https://github.com/rust-lang/book) after submitting this PR. These issues exist there, too. Should I submit another PR to update the rewrite?

[steveklabnik]

Yes please! That'd be great :)

[justsostephen]

Will do! :-)