DOC Fix some typos in the docs
Here's a few typos I found via `codespell`, first-timers are welcome to open a pull request to fix them
```
doc/source/ecosystem.rst:233: copyed ==> copied
doc/source/whatsnew/v0.24.1.rst:3: Whats ==> What's
doc/source/whatsnew/v0.16.2.rst:150: arithmetics ==> arithmetic
doc/source/whatsnew/v0.24.2.rst:3: Whats ==> What's
doc/source/whatsnew/v1.2.0.rst:183: Expecially ==> Especially
```