Small grammar, punctuation, and code style improvements to docs

[carols10cents]

changelog: Made small grammar, punctuation, and code style improvements to docs

I recently found some places in rust-lang/rust that had lists without spaces after commas, which led me to look for more places, which led me over here to find:

• Some similar lists in code examples that could use spaces after commas to be idiomatic Rust style
• Some lists in documentation text that didn't have spaces after commas, needed an Oxford comma (fight me), or were otherwise misformatted
• Some other grammar improvements in the area of the other changes

These changes should only be in user-facing documentation or output.

[rust-highfive]

r? @Manishearth

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[flip1995]

Not a native speaker, so I leave the decision about that/which to you. For me it sounds exactly the same. 😄

[flip1995]

You'll have to run cargo dev update_lints in the Clippy directory once though.

@bors delegate+

[bors]

✌️ @carols10cents can now approve this pull request

[carols10cents]

Whoops, sorry about that! I think I've fixed everything, sooooo

@bors r+

[bors]

📌 Commit 445466e has been approved by carols10cents

[bors]

⌛ Testing commit 445466e with merge 3e7c6de...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: carols10cents
Pushing 3e7c6de to master...