fix a bunch of typos found by codespell

[matthiaskrgr]

https://github.com/lucasdemarchi/codespell/

[rust-highfive]

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 Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed.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

Hm, looks like travis hangs...

test result: ok. 42 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
     Running target/debug/deps/jobserver-5f38de494ee6af35
running 3 tests
test jobserver_and_j ... ok
test jobserver_exists ... ok
test makes_jobserver_used has been running for over 60 seconds
No output has been received in the last 10m0s, this potentially indicates a stalled build or something wrong with the build itself.
Check the details on how to adjust your build configuration on: https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received
The build has been terminated

[alexcrichton]

@bors: r+

Thanks!

[bors]

📌 Commit 670a3df has been approved by alexcrichton

[bors]

⌛ Testing commit 670a3df with merge df089f4...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: alexcrichton
Pushing df089f4 to master...