Rollup merge of #61259 - JosephTLyons:mailmap-fixes, r=nikomatsakis

Rollup merge of #61259 - JosephTLyons:mailmap-fixes, r=nikomatsakis

Mailmap fixes

I've made a few fixes and additions to the .mailmap file.

- I've added my information to it, as I noticed it was popping up twice at the [Thanks](https://thanks.rust-lang.org/rust/all-time/) website (I've made contributions to the Rust Book).
- I noticed that @carols10cents‘ information was popping up in multiple places at the [Thanks](https://thanks.rust-lang.org/rust/all-time/) website and when running `git shortlog -s -e > out.txt`, and fixed her information
- I alphabetized the list using Atom's [Sort Lines package](https://github.com/atom/sort-lines)

The output from before and after running `git shortlog -s -e > out.txt` for Carol:
<img width="708" alt="Carol Before" src="https://user-images.githubusercontent.com/19867440/58472843-2d8ca880-8115-11e9-9624-d31ed23ae9b5.png">
<img width="523" alt="Carol After" src="https://user-images.githubusercontent.com/19867440/58472844-2d8ca880-8115-11e9-95c6-80b17cc04790.png">

The output from before and after running `git shortlog -s -e > out.txt` for myself:

<img width="489" alt="Joseph After" src="https://user-images.githubusercontent.com/19867440/58472941-6e84bd00-8115-11e9-8266-1d7fcd53d0bc.png">
<img width="421" alt="Joseph Before" src="https://user-images.githubusercontent.com/19867440/58472943-6e84bd00-8115-11e9-9fd2-d7ace7e3d636.png">