Clarifying OSX, adding issue with Install-Package (#2033)
Clarifying OSX, adding issue with Install-Package (#2033)

* Clarifying OSX, adding issue with Install-Package

- Changing first section to "non-Windows" and clarifying that most of these issues apply to both Linux & OSX.
- Fixed a few typos.
- Adding known issue with Install-Package per #1773

* Mac OSX -> macOS

Complying with convention used in #1934

* added alpha build # to install-package notice

* typo

* Typo

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